What’s Vulnerable › Vulnerabilities

CVE-2024-26134: CBOR2 decoder has potential buffer overflow

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2024-02-19 · updated 2026-06-17
• Weakness: CWE-120

Description

cbor2 provides encoding and decoding for the Concise Binary Object Representation (CBOR) (RFC 8949) serialization format. Starting in version 5.5.1 and prior to version 5.6.2, an attacker can crash a service using cbor2 to parse a CBOR binary by sending a long enough object. Version 5.6.2 contains a patch for this issue.

Affected products

• agronholm cbor2: from 5.5.1 before 5.6.2 — fixed in 5.6.2
• Fedoraproject Fedora: 38, 39, 40

How to fix

Upgrade to a fixed version: agronholm cbor2 5.6.2. Check the vendor advisory for mitigations.

References

• https://github.com/agronholm/cbor2/commit/387755eacf0be35591a478d3c67fe10618a6d542
• https://github.com/agronholm/cbor2/commit/4de6991ba29bf2290d7b9d83525eda7d021873df
• https://github.com/agronholm/cbor2/pull/204
• https://github.com/agronholm/cbor2/releases/tag/5.6.2
• https://github.com/agronholm/cbor2/security/advisories/GHSA-375g-39jq-vq7m
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BT42VXZMMMCSSHMA65KKPOZCXJEYHNR5/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GX524ZG2XJWFV37UQKQ4LWIH4UICSGEQ/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PWC3VU6YV6EXKCSX5GTKWLBZIDIJNQJY/
• https://github.com/agronholm/cbor2/commit/387755eacf0be35591a478d3c67fe10618a6d542
• https://github.com/agronholm/cbor2/commit/4de6991ba29bf2290d7b9d83525eda7d021873df
• https://github.com/agronholm/cbor2/pull/204
• https://github.com/agronholm/cbor2/releases/tag/5.6.2

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