Weakness (CWE)
CWE-754: Improper Check for Unusual or Exceptional Conditions
The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.
How to prevent it (7 mitigations)
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Requirements
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Choose languages with features such as exception handling that force the programmer to anticipate unusual conditions that may generate exceptions. Custom exceptions may need to be developed to handle unusual business-logic conditions. Be careful not to pass sensitive exceptions back to the user (CWE-209, CWE-248).
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Implementation
Check the results of all functions that return a value and verify that the value is expected.
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Implementation
If using exception handling, catch and throw specific exceptions instead of overly-general exceptions (CWE-396, CWE-397). Catch and handle exceptions as locally as possible so that exceptions do not propagate too far up the call stack (CWE-705). Avoid unchecked or uncaught exceptions where feasible (CWE-248).
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Implementation
Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success.
If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files.
Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.
Exposing additional information to a potential attacker in the context of an exceptional condition can help the attacker determine what attack vectors are most likely to succeed beyond DoS.
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Implementation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
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Architecture and Design, Implementation
If the program must fail, ensure that it fails gracefully (fails closed). There may be a temptation to simply let the program fail poorly in cases such as low memory conditions, but an attacker may be able to assert control before the software has fully exited. Alternately, an uncontrolled failure could cause cascading problems with other downstream components; for example, the program could send a signal to a downstream process so the process immediately knows that a problem has occurred and has a better chance of recovery.
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Architecture and Design
Use system limits, which should help to prevent resource exhaustion. However, the product should still handle low resource conditions since they may still occur.
Source: MITRE CWE-754
535 results · Feed
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Critical 9.3
CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability that could cause arbitrary code execution, …
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Medium 4.7
DOMPurify through 3.3.3 Cross-Site Scripting via IN_PLACE mode
DOMPurify through 3.3.3 fails to sanitize DOM elements passed via IN_PLACE mode when the element originates from a different window/realm (e.g., an iframe's contentDocument). A cross-realm instanceof check in the private _isNode() function returns false for f…
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Medium 5.9
Libunbound applications configured with 'unwanted-reply-threshold' could eventually be abruptly terminated
With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and libunbound needs to call 'libworker_alloc_cleanup…
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Medium 6.5
SurrealDB before 3.1.0 Denial of Service via LIVE Query
SurrealDB versions before 3.1.0 contain a denial of service vulnerability where malicious LIVE queries with WHERE clauses that evaluate to errors cause all CREATE, UPDATE, and DELETE operations on the watched table to fail. An authenticated user with only sel…
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High 7.5
SurrealDB before 3.1.0 Denial of Service via malformed RPC use
SurrealDB versions before 3.1.0 contain a denial of service vulnerability in the RPC use handler that panics when db is set without a namespace. Unauthenticated attackers can send a malformed WebSocket message to the /rpc endpoint to crash the server process.
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Low 3.1
Insufficient Input Validation in DevOps Loop
HCL DevOps Loop is affected by insufficient input validation that allows special characters where they should be restricted. This may result in unintended application behavior under certain conditions.
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Medium 6.5
Posting a malicious markdown image crashes the Mattermost Desktop App
Mattermost Desktop App versions <=6.2 5.5.13 6.0.2.0 fail to properly null check when checking for headers in the Mattermost Desktop App which allows any user to crash another channel members Desktop App via posting a malicious link with an embedded image tha…
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Medium 4.7
Junos OS: MX Series: For subscribers configured on static interfaces, input filters are not in effect
An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on MX Series allows adjacent subscribers to bypass configured firewall filters. On MX Series devices with MPC10/11, LC4800…
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Medium 5.9
Junos OS: MX Series with SPC3, SRX Series: Specific packet in response to a TCP connection establishment by the affected device can crash the PFE
An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX with SPC3 and SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). When …
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Medium 6.5
Junos OS: QFX10000 Series: IPv6 multicast traffic received on non-IRB interfaces causes a multicast flood
An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on QFX10000 Series allows an unauthenticated, adjacent attacker to cause a Denial-of-Service (DoS). On all QFX10000 platfo…
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Medium 6.5
Junos OS and Junos OS Evolved: When a specifically malformed BGP route update is received RPD crashes
An Improper Check for Unusual or Exceptional Conditions vulnerability in the routing protocol daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker sending a specific BGP update over an established BGP ses…
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Medium 5.9
Junos OS Evolved: PTX Series: Receipt of repeated ECMP routing updates results in PFE crash
An Improper Check for Unusual or Exceptional Conditions vulnerability in the advanced forwarding toolkit (evo-aftmand) of Juniper Networks Junos OS Evolved on PTX Series allows an unauthenticated network-based attacker generating continuous routing updates, r…
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Medium 4.6
PAN-OS: Denial of Service Vulnerabilities in Network Traffic Processing
Multiple denial of service vulnerabilities in Palo Alto Networks PAN-OS® software allow an unauthenticated attacker with network access to cause a denial of service (DoS) condition by sending specially crafted network traffic to or through a dataplane interfa…
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Medium 6.5
CoreWCF: Kafka consume pump halts permanently on a Kafka tombstone (null-value record), causing persistent endpoint denial of service.
CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, a CoreWCF service listening on a Kafka topic stops processing new records from that topic when KafkaTransportPump receives a null-value tom…
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Medium 6.3
Phoenix JavaScript presence client crashes on presence keys colliding with Object.prototype members in Presence.syncState/syncDiff
Improper Check for Unusual or Exceptional Conditions vulnerability in phoenixframework phoenix (Presence JavaScript client) allows an attacker with ordinary channel access to cause a persistent client-side denial of service against every viewer of a presence …
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Low 2.3
FOSSBilling: Payment amount not validated in PayPalEmail adapter allows invoice underpayment
FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, the PayPalEmail payment adapter accepts PayPal IPN callbacks and credits the IPN-supplied amount (`mc_gross`) to the client's balance without validating it agains…
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Medium 5.9
ImageMagick: Heap Buffer Overflow in ImageMagick MVG decoder
ImageMagick is free and open-source software used for editing and manipulating digital images. Prior to versions 6.9.13-51 and 7.1.2-26, a heap buffer overflow occurs in the MVG decoder that could result in an out of bounds write when processing a crafted ima…
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Medium 5.3
protobufjs: Schema-derived names can shadow runtime-significant properties
protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 8.6.0 and 7.6.3, protobufjs accepted certain schema-derived names that could collide with properties used by protobufjs runtime helpers. The known affected names are fields name…
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High 8.7
Typesense: Unauthenticated Denial of Service in the Typesense /multi_search Endpoint
Typesense is a fast, typo-tolerant search engine. Prior to versions 29.1 and 30.2, there is an unauthenticated denial-of-service vulnerability in the /multi_search endpoint. A specially crafted request can trigger an unhandled exception during request process…
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Medium 4.6
PAN-OS: Denial of Service (DoS) in Tunnel Traffic Processing
A memory corruption vulnerability in the processing of tunnel traffic in Palo Alto Networks PAN-OS® software allows an authenticated user to initiate system reboots using a maliciously crafted packet. Repeated attempts to initiate a reboot causes the firewall…
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High 7.5
Nimiq network-libp2p: DHT query poisoning via first-record verification failure
Nimiq is a Rust implementation of the Nimiq Proof-of-Stake protocol based on the Albatross consensus algorithm. Prior to version 1.4.0, iIn handle_dht_get(), the DhtResults accumulator is only initialized when the first DHT record passes verification. If the …
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High 7.5
OpenTelemetry eBPF Instrumentation: Postgres BIND parsing can panic on malformed payloads
OpenTelemetry eBPF Instrumentation provides eBPF instrumentation based on the OpenTelemetry standard. Prior to version 0.9.0, the Postgres protocol parser assumes BIND message payloads contain a valid NUL-terminated portal name. A crafted empty or unterminate…
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Low 2.4
Indian Scout Bobber 2025 Infotainment Digital Round skips PIN entry when WCM is silent at boot
Incorrect behavior order in the Infotainment / Digital Round display of the Indian Motorcycle Scout Bobber + Tech 2025 model year allows an adjacent-network attacker to bypass the PIN entry screen. The Infotainment uses presence of Wireless Control Module (WC…
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Low 2.4
Indian Scout Bobber 2025 Infotainment Digital Round skips PIN entry when WCM is silent at boot
Incorrect behavior order in the Infotainment / Digital Round display of the Indian Motorcycle Scout Bobber + Tech 2025 model year allows an adjacent-network attacker to bypass the PIN entry screen. The Infotainment uses presence of Wireless Control Module (WC…
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Medium 4.6
Indian Scout Bobber 2025 WCM CAN bus-off attack silently bypasses anti-theft shutdown
Expected behavior violation in the in-vehicle network of the Indian Motorcycle Scout Bobber + Tech 2025 model year allows an adjacent-network attacker to bypass the motorcycle's anti-theft shutdown by forcing the Wireless Control Module (WCM) into the CAN bus…
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Medium 4.6
Indian Scout Bobber 2025 WCM voltage-based shutdown
Improper handling of physical conditions in the bike-shutdown control of the Indian Motorcycle Scout Bobber + Tech 2025 model year allows a physical attacker with access to the Wireless Control Module (WCM) wiring harness to bypass the anti-theft shutdown. Th…
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High 7.4
SAML SSO - Service Provider - Critical - Authentication bypass - SA-CONTRIB-2026-031
Improper Check for Unusual or Exceptional Conditions vulnerability in Drupal SAML SSO - Service Provider allows Privilege Escalation. This issue affects SAML SSO - Service Provider: from 0.0.0 before 3.1.4.
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High 7.5
Lakeside SysTrack Agent LsiAgent.exe Out-of-Bounds Read via UDP
Lakeside SysTrack Agent versions prior to 11.2.1.28, 11.3.0.38, 11.4.0.24, 11.5.0.15 contain an out-of-bounds read vulnerability in the Command ID 30 UDP packet handler that allows remote attackers to crash the application by sending a specially crafted UDP p…
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High 7.5
free5GC: PCF npcf-smpolicycontrol POST /sm-policies panics on downstream UDR/OpenAPI 404 via nil pointer dereference
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's PCF POST /npcf-smpolicycontrol/v1/sm-policies handler (HandleCreateSmPolicyRequest) panics with a nil-pointer dereference when a downstream OpenAPI consumer call (UDR l…
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Medium 6.5
free5GC: PCF npcf-policyauthorization POST /app-sessions panics on suppFeat=1 with missing AfRoutReq via nil pointer dereference
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's PCF POST /npcf-policyauthorization/v1/app-sessions handler panics on a single authenticated request whose ascReqData.suppFeat == "1" (enabling traffic-routing feature n…
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High 7.5
free5GC: NEF 3gpp-pfd-management PATCH applications/{appId} panics on UDR access failure due to nil ProblemDetails dereference
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF PATCH /3gpp-pfd-management/v1/{afId}/transactions/{transId}/applications/{appId} handler panics with a nil-pointer dereference when the upstream UDR call fails AND …
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Medium 6.5
free5GC: UDR nudr-dr DELETE amf-subscriptions panics on missing UE state via nil interface type assertion (single authenticated request)
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's UDR nudr-dr DELETE /subscription-data/{ueId}/{servingPlmnId}/ee-subscriptions/{subsId}/amf-subscriptions handler panics on a single authenticated request against a fres…
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High 8.1
Improper check for unusual or exceptional conditions vulnerability in SSO in Synology DiskStation Manager (DSM) before …
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Medium 6.5
Server panic via outgoing webhook responses
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to filter nil elements from outgoing webhook attachment payloads before processing, which allows an authenticated user to cause a denial of service (server proc…
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Medium 4.3
nimiq-blockchain: network-libp2p untrusted peer can crash address book via empty peer contact addresses
nimiq-blockchain provides persistent block storage for Nimiq's Rust implementation. In versions 1.3.0 and prior, network-libp2p discovery accepts signed PeerContact updates from untrusted peers and stores them in a peer contact book, eventually leading to add…
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High 7.5
Invalid handling of CLASS != IN
Multiple flaws have been identified in `named` related to the handling of DNS messages whose CLASS is not Internet (`IN`) — for example, `CHAOS` or `HESIOD`, or DNS messages that specify meta-classes (`ANY` or `NONE`) in the question section. Specially crafte…
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Low 3.7
Node View Permissions - Moderately critical - Access bypass - SA-CONTRIB-2026-034
Improper Check for Unusual or Exceptional Conditions vulnerability in Drupal Node View Permissions allows Forceful Browsing. This issue affects Node View Permissions: from 0.0.0 before 1.7.0, from 2.0.0 before 2.0.1.
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Medium 5.5
Improper Check for Unusual or Exceptional Conditions vulnerability in Samsung Open Source Escargot allows Input Data Ma…
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Low 3.5
Calling window.close() from server-side content causes crash in the Mattermost Desktop App
Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent server-rendered content from closing an underlying application view in the Mattermost Desktop App which allows a malicious server or plugin to crash the desktop client via invoking {{window.…
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Medium 4.3
SVG content served through Mattermost image proxy despite Content-Type restrictions causes client-side denial of service
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG…