Vendor
http4s
31 known vulnerabilities.
http4s at a glance
Show as table
| Month | Vulnerabilities | Critical |
|---|---|---|
| Nov 2026 | 0 | 0 |
| Oct 2026 | 0 | 0 |
| Sep 2026 | 20 | 2 |
| Aug 2026 | 3 | 0 |
| Jul 2026 | 0 | 0 |
| Jun 2026 | 0 | 0 |
| May 2026 | 0 | 0 |
| Apr 2026 | 0 | 0 |
| Mar 2026 | 0 | 0 |
| Feb 2026 | 0 | 0 |
| Jan 2026 | 0 | 0 |
| Dec 2025 | 0 | 0 |
| Nov 2025 | 0 | 0 |
| Oct 2025 | 0 | 0 |
| Sep 2025 | 1 | 0 |
| Aug 2025 | 0 | 0 |
| Jul 2025 | 0 | 0 |
| Jun 2025 | 0 | 0 |
| May 2025 | 0 | 0 |
| Apr 2025 | 0 | 0 |
| Mar 2025 | 0 | 0 |
| Feb 2025 | 0 | 0 |
| Jan 2025 | 0 | 0 |
| Dec 2024 | 0 | 0 |
Products
31 results · Feed
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Critical 9.3
http4s-scala-xml has an XML External Entity (XXE) processing issue
http4s-scala-xml provides `EntityDecoder[F, scala.xml.Elem]` instances that parse XML message bodies. Prior to versions 0.24.1 and 1.0.0-M39, these decoders used a `javax.xml.parsers.SAXParserFactory` obtained from `SAXParserFactory.newInstance` without any s…
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High 7.5
Http4s: Ember HTTP/2 buffers a frame's declared payload before checking SETTINGS_MAX_FRAME_SIZE
Http4s is a Scala interface for HTTP services. Prior to 0.23.37 and 1.0.0-M48, Ember’s HTTP/2 read loop parses a frame’s 24-bit declared length but waits to buffer the entire payload before comparing it with SETTINGS_MAX_FRAME_SIZE. An unauthenticated peer ca…
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Medium 5.9
Http4s: DigestAuth allows replay of captured requests
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, DigestAuth replay protection records lastNc plus one instead of the highest nonce-count value it has accepted. When a legitimate client sends noncontiguous nc values because of par…
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High 7.5
Http4s Ember HTTP/2: unbounded inbound body buffering
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HTTP/2 flow-control window is replenished according to bytes received from the network rather than bytes consumed by the application, while each stream stores DATA in an un…
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High 7.5
Http4s Ember HTTP/2: unbounded continuation frame accumulation
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, When Ember receives an HTTP/2 HEADERS or PUSH_PROMISE frame without END_HEADERS, H2Connection buffers the header block and subsequent CONTINUATION fragments without a size bound. A…
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High 7.5
Http4s Ember HTTP/2: does not enforce SETTINGS_MAX_CONCURRENT_STREAMS
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, An Ember server with HTTP/2 enabled through withHttp2 does not enforce SETTINGS_MAX_CONCURRENT_STREAMS for peer-created streams. One unauthenticated connection can open an unbounde…
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High 8.7
Http4s: Ember Server accepts duplicate Content-Length headers
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HTTP/1.1 parser accepts differing duplicate Content-Length headers and uses the last value instead of rejecting the message. When an Ember server is behind a keep-alive int…
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High 7.5
Http4s: WebSocket decoder accepts negative length, causing infinite decode loop
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, WebSocket FrameTranscoder.bodyLength rejects extended payload lengths above Integer.MAX_VALUE but permits negative 64-bit lengths. A remote client that completes a WebSocket handsh…
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Medium 6.8
Http4s: CookieJar middleware matches by substring, leaking cookies cross-origin
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The CookieJar client middleware uses unanchored substring checks instead of RFC 6265 domain and path matching when deciding whether to attach a stored cookie. A cookie for example.…
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High 8.7
Http4s: Ember Transfer-Encoding value parsing (TE.CL / TE.0 request smuggling)
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HeaderP.parse uses a case-sensitive substring test for the Transfer-Encoding value and decodes header bytes with the platform default charset. Values such as Chunked are no…
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Medium 5.9CVE-2026-69212 Public exploit
Http4s: FollowRedirect middleware leaks credentials over https->http same-authority redirect
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The FollowRedirect client middleware strips Authorization and Cookie headers only when a redirect changes authority, but authority comparison excludes the URI scheme. A same-author…
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High 7.5
Http4s Ember HTTP/2: unbounded outbound frame queue
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember HTTP/2 serializes outbound frames through one unbounded queue consumed by writeLoop. When the peer stops reading, an unauthenticated HTTP/2 client can continue sending PING, …
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Medium 6.8
Http4s: CookieJar middleware accepts arbitrary Set-Cookie domain
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The CookieJar client middleware stores a response cookie’s Domain attribute without checking that it domain-matches the host that supplied the cookie or rejecting public suffixes. …
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Medium 5.9
Http4s: ResourceService and Webjar Service path escape via percent-encoded separators
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, ResourceService and WebjarService decode each URL path segment but reject only segments exactly equal to an empty string, a dot, or two dots. A request containing percent-encoded s…
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Medium 5.4
Http4s: Ember chunk parser lenience (TE.TE request smuggling)
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an …
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Medium 4.8
Http4s: Set-Cookie rendering does not escape attribute delimiters
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, ResponseCookie.render writes attacker-influenced name, content, domain, path, and extension values without neutralizing semicolons or control characters. An application that constr…
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High 7.5
Http4s: WebSocket decoder accepts unbounded message sizes
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The shared WebSocket decoder permits unbounded message buffering because defragmentation accumulates fragments without a limit and FrameTranscoder accepts declared lengths up to In…
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High 7.5
Http4s: DigestAuth nonce map grows unbounded
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, the DigestAuth server middleware removes fresh nonces and stops eviction at the first stale nonce because its stale-nonce comparison is inverted. On an application that protects at…
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Critical 9.2
Http4s: Ember accepts Transfer-Encoding combined with Content-Length (CL.TE request smuggling)
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember HTTP/1.1 does not reject messages containing both Transfer-Encoding and Content-Length, so an intermediary and Ember can select different body framing rules. When ember-serve…
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High 7.4
blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze's Java wire parser
blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and from 1.0.0-M1 until 1.0.0-M42, five HTTP/1.1 conformance laxities in the hand-written Java parser under http/src/main/java/org/http4s/blaze/http/par…
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High 8.2
Http4s: HTTP/2 Denial of Service with Ember Backend
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, an unauthenticated HTTP/2 peer can cause an out-of-memory denial of service in the Ember backend with HTTP/2 enabled. The Hpack wrapper in ember-core/shared/src/main/scala/org/http…
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High 7.4
blaze: Chunked-body trailer fields promoted into Request.headers in blaze-server (front-end header-sanitization bypass)
blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and 1.0.0-M42, blaze-server can merge HTTP/1.1 chunked-body trailer fields into Request.headers. Because trailer fields are attacker-controlled, an unau…
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High 7.5
http4s-blaze-server: Unbounded WebSocket message aggregation
Http4s (http4s-blaze-server) is a minimal, idiomatic Scala interface for HTTP services. Prior to 0.23.18 and 1.0.0-M42, http4s-blaze-server aggregates fragments of an incoming WebSocket message with no limit on total size or fragment count. A client that comp…
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Medium 6.3
Http4s vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section
Http4s is a Scala interface for HTTP services. In versions from 1.0.0-M1 to before 1.0.0-M45 and before 0.23.31, http4s is vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section. This vulnerability could enable attackers to bypa…
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High 7.5
Http4s has fatal error parsing User-Agent and Server headers
Http4s is a Scala interface for HTTP services. Starting with version 0.1.0 and prior to versions 0.21.34, 0.22.15, 0.23.17, and 1.0.0-M38, the `User-Agent` and `Server` header parsers are susceptible to a fatal error on certain inputs. In http4s, modeled head…
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High 8.7
Response Splitting from unsanitized headers in http4s
http4s is an open source scala interface for HTTP. In affected versions http4s is vulnerable to response-splitting or request-splitting attacks when untrusted user input is used to create any of the following fields: Header names (`Header.name`å), Header valu…
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Critical 9.1
Default CORS config allows any origin with credentials
Http4s is a minimal, idiomatic Scala interface for HTTP services. In http4s versions 0.21.26 and prior, 0.22.0 through 0.22.2, 0.23.0, 0.23.1, and 1.0.0-M1 through 1.0.0-M24, the default CORS configuration is vulnerable to an origin reflection attack. The mid…
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Medium 5.8
StaticFile.fromUrl can leak presence of a directory
Http4s is a Scala interface for HTTP services. `StaticFile.fromUrl` can leak the presence of a directory on a server when the `URL` scheme is not `file://`, and the URL points to a fetchable resource under its scheme and authority. The function returns `F[Non…
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High 7.5
Unbounded connection acceptance in http4s-blaze-server
Http4s (http4s-blaze-server) is a minimal, idiomatic Scala interface for HTTP services. Http4s before versions 0.21.17, 0.22.0-M2, and 1.0.0-M14 have a vulnerability which can lead to a denial-of-service. Blaze-core, a library underlying http4s-blaze-server, …
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High 7.5
Unbounded connection acceptance leads to file handle exhaustion
blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. All servers running blaze-core before version 0.14.15 are affected by a vulnerability in which unbounded connection acceptance leads to file handle exhaustion. Blaze, ac…
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High 7.6
Local file inclusion vulnerability in http4s
http4s before versions 0.18.26, 0.20.20, and 0.21.2 has a local file inclusion vulnerability. This vulnerability applies to all users of org.http4s.server.staticcontent.FileService, org.http4s.server.staticcontent.ResourceService and org.http4s.server.staticc…