Moderate severityOSV Advisory· Published Dec 31, 2025· Updated Jan 2, 2026
CBORDecoder reuse can leak shareable values across decode calls
CVE-2025-68131
Description
cbor2 provides encoding and decoding for the Concise Binary Object Representation (CBOR) serialization format. Starting in version 3.0.0 and prior to version 5.8.0, whhen a CBORDecoder instance is reused across multiple decode operations, values marked with the shareable tag (28) persist in memory and can be accessed by subsequent CBOR messages using the sharedref tag (29). This allows an attacker-controlled message to read data from previously decoded messages if the decoder is reused across trust boundaries. Version 5.8.0 patches the issue.
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Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
cbor2PyPI | >= 3.0.0, < 5.8.0 | 5.8.0 |
Affected products
17- osv-coords16 versionspkg:apk/chainguard/authentikpkg:apk/chainguard/authentik-fipspkg:apk/chainguard/authentik-go-serverpkg:apk/chainguard/authentik-go-server-fipspkg:apk/chainguard/localstackpkg:apk/chainguard/localstack-compatpkg:apk/chainguard/py3.10-vllm-cuda-12.4pkg:apk/chainguard/py3.12-vllm-cuda-12.4pkg:apk/chainguard/py3-vllm-cuda-12.4pkg:apk/chainguard/tritonserver-backend-vllm-cuda-12.9pkg:apk/chainguard/tritonserver-backend-vllm-meta-cuda-12.9pkg:pypi/cbor2pkg:rpm/opensuse/python-cbor2&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/python-cbor2&distro=openSUSE%20Tumbleweedpkg:rpm/suse/python-cbor2&distro=SUSE%20Linux%20Enterprise%20Server%2016.0pkg:rpm/suse/python-cbor2&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20applications%2016.0
< 2025.10.3-r2+ 15 more
- (no CPE)range: < 2025.10.3-r2
- (no CPE)range: < 2025.10.3-r1
- (no CPE)range: < 2025.10.3-r2
- (no CPE)range: < 2025.10.3-r0
- (no CPE)range: < 4.12.0-r1
- (no CPE)range: < 4.12.0-r1
- (no CPE)range: < 0.13.0-r1
- (no CPE)range: < 0.13.0-r1
- (no CPE)range: < 0.13.0-r1
- (no CPE)range: < 25.9.0_git20251112-r4
- (no CPE)range: < 25.9.0_git20251112-r4
- (no CPE)range: >= 3.0.0, < 5.8.0
- (no CPE)range: < 5.6.5-160000.4.1
- (no CPE)range: < 5.8.0-2.1
- (no CPE)range: < 5.6.5-160000.4.1
- (no CPE)range: < 5.6.5-160000.4.1
Patches
Vulnerability mechanics
References
6- github.com/advisories/GHSA-wcj4-jw5j-44whghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2025-68131ghsaADVISORY
- github.com/agronholm/cbor2/commit/f1d701cd2c411ee40bb1fe383afe7f365f35abf0ghsaWEB
- github.com/agronholm/cbor2/pull/268ghsax_refsource_MISCWEB
- github.com/agronholm/cbor2/security/advisories/GHSA-wcj4-jw5j-44whghsax_refsource_CONFIRMWEB
- github.com/pypa/advisory-database/tree/main/vulns/cbor2/PYSEC-2025-90.yamlghsaWEB
News mentions
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