UBUNTU-CVE-2026-62995

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Source
https://ubuntu.com/security/CVE-2026-62995
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-62995.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-62995
Upstream
Published
2026-07-29T19:16:00Z
Modified
2026-08-06T03:13:29.221326435Z
Severity
  • 2.3 (Low) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/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. in versions 1.7.1 and prior, joserfc accepts JWTs with trailing padding (==) which are not conforming to the JOSE specifications. This leads to malleability of the JWTs when consumed by joserfc. Depending on this application this might or not be an issue. This could lead to bypass of token revocation or anti-replay protection when implemented as a deny list of tokens or a deny list of token hashes. Note that ECDSA JWS are always malleable because of the malleability of ECDSA signatures (first test case in the code bellow). This makes a scheme which assumes that JWTs are not malleable brittle. However for other signatures (or MAC) schemes it might make sense to assume non malleability of the token. This issue has been fixed in version 1.7.2.

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
0Unknown 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_version": "1.6.2-1",
            "binary_name": "python3-joserfc"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-62995.json"