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Vulnerability record · CVE-2025-68131 · published 31 December 2025

CVE-2025-68131: Agronholm cbor2 vulnerability

AAgronholm · Cbor2

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.

5.5 CVSS 4.0 Medium EPSS 0.46% · top 62.7% CWE-212 · CWE-212
5.5CVSS 4.0 base score
0.46%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 3 tagged exploit
17 Jun 2026Last modified by NVD

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.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/agronholm/cbor2/pull/268 ExploitPatch
https://github.com/agronholm/cbor2/security/advisories/GHSA-wcj4-jw5j-44wh ExploitVendor Advisory
https://github.com/agronholm/cbor2/security/advisories/GHSA-wcj4-jw5j-44wh ExploitVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.5CVE-2026-26209Agronholm cbor2 vulnerabilitycbor2 provides encoding and decoding for the Concise Binary Object Representation (CBOR) serialization format. Versions prior to 5.9.0 are vulnerable…EPSS 0.65%7.5CVE-2025-64076Agronholm cbor2 vulnerabilityMultiple vulnerabilities exist in cbor2 through version 5.7.0 in the decode_definite_long_string() function of the C extension decoder (source/decode…EPSS 0.46%7.5CVE-2024-26134Agronholm cbor2 classic buffer overflow vulnerabilitycbor2 provides encoding and decoding for the Concise Binary Object Representation (CBOR) (RFC 8949) serialization format. Starting in version 5.5.1 a…EPSS 1.2%

Source: NIST National Vulnerability Database (record CVE-2025-68131), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.