UBUNTU-CVE-2026-49852

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Source

https://ubuntu.com/security/CVE-2026-49852

Import Source

https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49852.json

JSON Data

https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-49852

Upstream

CVE-2026-49852

Published

2026-07-17T20:17:00Z

Modified

2026-07-29T10:18:35Z

Severity

8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N CVSS Calculator
Ubuntu - medium

Summary

[none]

Details

joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.6.8, joserfc.jwt.decode accepts attacker-forged HMAC-signed tokens when the caller-supplied verification key is the empty string or None, because HMACAlgorithm.sign and HMACAlgorithm.verify in src/joserfc/_rfc7518/jws_algs.py pass the output of OctKey.get_op_key(...) to hmac.new(...) and OctKey.import_key in src/joserfc/_rfc7518/oct_key.py only emits a SecurityWarning for keys shorter than 14 bytes without rejecting zero-length input. This issue is fixed in version 1.6.8.

References

Affected packages

Ubuntu:26.04:LTS / joserfc

Package

Name: joserfc
Purl: pkg:deb/ubuntu/joserfc?arch=source&distro=resolute

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Affected versions

1.*

1.2.2-1

1.4.0-1

1.4.1-1

1.4.3-1

1.5.0-1

1.6.2-1

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "python3-joserfc",
            "binary_version": "1.6.2-1"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49852.json"