Summary
Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2026-5172: A buffer overflow in dnsmasq's extract_addresses() function allows an attacker to trigger a heap out-of-bounds read and crash by exploiting a malformed DNS response, enabling extract_name() to advance the pointer past the record's end. CVE-2026-4893: An information disclosure vulnerability in dnsmasq allows remote attackers to bypass source checks via a crafted DNS packet with RFC 7871 client subnet information. CVE-2026-4892: A heap-based out-of-bounds write vulnerability in the DHCPv6 implementation of dnsmasq allows local attackers to execute arbitrary code with root privileges via a crafted DHCPv6 packet. CVE-2026-4891: A heap-based out-of-bounds read vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet. CVE-2026-4890: A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet. CVE-2026-13002: A flow has been identified into dnssec.c library, causing an infinite loop to dnsmasq service. An attacker who controls any DNSSEC-signed zone can hang the dnsmasq process with a single crafted response, killing all DNS resolution for its clients.
Fixed packages 5
| Release | Package | Fixed in |
|---|---|---|
| Amazon Linux · 2023 | dnsmasq | 0:2.90-1.amzn2023.0.3 |
| Amazon Linux · 2023 | dnsmasq-debuginfo | 0:2.90-1.amzn2023.0.3 |
| Amazon Linux · 2023 | dnsmasq-debugsource | 0:2.90-1.amzn2023.0.3 |
| Amazon Linux · 2023 | dnsmasq-utils | 0:2.90-1.amzn2023.0.3 |
| Amazon Linux · 2023 | dnsmasq-utils-debuginfo | 0:2.90-1.amzn2023.0.3 |
Vulnerabilities 6
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High 8.4
CVE-2026-4892
A heap-based out-of-bounds write vulnerability in the DHCPv6 implementation of dnsmasq allows local attackers to execute arbitrary code with root privileges via a crafted DHCPv6 packet.
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High 7.5
CVE-2026-4890
A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.
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High 7.3CVE-2026-5172 Public exploit
CVE-2026-5172
A buffer overflow in dnsmasq’s extract_addresses() function allows an attacker to trigger a heap out-of-bounds read and crash by exploiting a malformed DNS response, enabling extract_name() to advance the pointer past the record’s end.
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Medium 5.3
CVE-2026-4891
A heap-based out-of-bounds read vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.
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Medium 5.3CVE-2026-4893 Public exploit
CVE-2026-4893
An information disclosure vulnerability in dnsmasq allows remote attackers to bypass source checks via a crafted DNS packet with RFC 7871 client subnet information.
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Medium 4.4CVE-2026-13002 Rejected
Rejected as this CVE is duplicate to CVE-2026-4890.
References
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-13002.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-4890.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-4891.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-4892.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-4893.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-5172.html