# CVE-2026-13002: Dnsmasq: infinite loop dos in dnssec nsec/nsec3 type bitmap parsing

CVE-2026-13002 is fixed in 5 products on 1 platform, first by ALAS2023-2026-1729, released May 25, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-13002
- Priority: Routine
- CVSS: 4.4 (Moderate)
- EPSS: n/a
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 25, 2026
- Weakness: Loop with Unreachable Exit Condition ('Infinite Loop')
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-13002

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | dnsmasq amzn 2023 | 2.90-1.amzn2023.0.3 | [ALAS2023-2026-1729](https://patchblox.com/security/data/fix/linux/alas2023-2026-1729.md) | May 25, 2026 |
| Linux | dnsmasq-debuginfo amzn 2023 | 2.90-1.amzn2023.0.3 | [ALAS2023-2026-1729](https://patchblox.com/security/data/fix/linux/alas2023-2026-1729.md) | May 25, 2026 |
| Linux | dnsmasq-debugsource amzn 2023 | 2.90-1.amzn2023.0.3 | [ALAS2023-2026-1729](https://patchblox.com/security/data/fix/linux/alas2023-2026-1729.md) | May 25, 2026 |
| Linux | dnsmasq-utils amzn 2023 | 2.90-1.amzn2023.0.3 | [ALAS2023-2026-1729](https://patchblox.com/security/data/fix/linux/alas2023-2026-1729.md) | May 25, 2026 |
| Linux | dnsmasq-utils-debuginfo amzn 2023 | 2.90-1.amzn2023.0.3 | [ALAS2023-2026-1729](https://patchblox.com/security/data/fix/linux/alas2023-2026-1729.md) | May 25, 2026 |

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Data as of 2026-11-10T13:56:55Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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