CVE-2026-62995

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Source
https://cve.org/CVERecord?id=CVE-2026-62995
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-62995.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-62995
Aliases
  • GHSA-5jhw-7jv7-qcqq
Downstream
Published
2026-07-29T18:27:06.518Z
Modified
2026-07-30T04:03:24.399503655Z
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
Summary
joserfc accepts JWT with padding, leading to JWT malleability
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.

Database specific 
{
    "cwe_ids": [
        "CWE-345"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62995.json",
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/authlib/joserfc

Affected ranges

Type
GIT
Repo
https://github.com/authlib/joserfc
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
54d6c3f290867055d0e8d3c49f979dcd8ee739fb
Database specific 
{
    "source": "AFFECTED_FIELD",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "1.7.2"
        }
    ]
}

Affected versions

0.*
0.10.0
0.11.0
0.11.1
0.12.0
0.2.0
0.3.0
0.4.0
0.5.0
0.6.0
0.7.0
0.8.0
0.9.0
1.*
1.0.0
1.0.1
1.0.2
1.0.3
1.0.4
1.1.0
1.2.0
1.2.1
1.2.2
1.3.0
1.3.1
1.3.2
1.3.3
1.4.0
1.4.1
1.4.3
1.5.0
1.6.0
1.6.1
1.6.2
1.6.3
1.6.4
1.6.5
1.6.7
1.7.0
1.7.1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-62995.json"