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Fencer Vulns
high 7.5

CVE-2024-26134 json

CBOR2 decoder has potential buffer overflow

published 2024-02-19 2 y ago modified 2026-06-17 4 mo ago also GHSA-375g-39jq-vq7m , PYSEC-2024-155 , EUVD-2024-0204

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 67%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi cbor2 5.6.2
  • agronholm cbor2 5.6.2
  • cbor2 Debian 14, Debian 13 5.6.2-1

debian advisories DEBIAN-CVE-2024-26134

  • python-cbor2 SLES for SAP applications 16.0, SLES 16.0 5.6.5-160000.3.1

suse advisories SUSE-SU-2025:21168-1

  • python-cbor2 openSUSE Leap 16.0 5.6.5-160000.3.1
  • python-cbor2 openSUSE Tumbleweed 5.6.5-2.1

opensuse advisories openSUSE-SU-2025:20133-1openSUSE-SU-2025:14733-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-26134 updated cvss 7.5

cbor2: Potential buffer overflow in CBOR2 decoder

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

1.17% chance of exploitation in the next 30 days, higher than 67% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/agronholm/cbor2/security/advisories/GHSA-375g-39jq-vq7m referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi cbor2
>=5.5.1, <5.6.2
5.6.2

Affected products

  • agronholm cbor2

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.