DEBIAN-CVE-2026-65632

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Source
https://security-tracker.debian.org/tracker/CVE-2026-65632
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-65632.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-65632
Upstream
Published
2026-10-26T20:17:59Z
Modified
2026-10-27T17:00:07Z
Severity
  • 5.1 (Medium) CVSS_V4 - CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/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:X/V:X/RE:X/U:X CVSS Calculator
Summary
[none]
Details

The jose library accepts ECDSA (ES256, ES256K, ES384, and ES512) JWS signatures of a non-canonical length. When verifying an ECDSA signature, jose_jwk_kty_ec:verify/4 in src/jwk/jose_jwk_kty_ec.erl splits the raw signature in half by its actual byte length (split_binary(Signature, byte_size(Signature) div 2)) instead of enforcing the fixed length required by RFC 7518 ยง3.4, and then decodes each half with crypto:bytes_to_integer/1, which ignores leading zero bytes. As a result, an attacker who holds one valid token can prepend leading zero bytes to each of the R and S halves to produce longer signatures that still split evenly and decode to the same (r, s) pair, so many distinct signature byte strings all verify against the same key (signature malleability). This does not allow forging new payloads or impersonating a signer, because the underlying (r, s) values are unchanged. It does defeat any security control that assumes a valid token or its signature is unique, such as token-revocation-by-hash, replay or idempotency caches, and deduplication logic. This issue affects jose: from 1.0.0 before 1.11.13.

References

Affected packages

Debian:12 / erlang-jose

Package

Name
erlang-jose
Purl
pkg:deb/debian/erlang-jose?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.11.5-1
1.11.6-1~bpo12+1
1.11.6-1
1.11.10-1~bpo12+1
1.11.10-1
1.11.12-1
1.11.12-1.1
1.11.12-2~bpo13+1
1.11.12-2
1.11.12-3~bpo13+1
1.11.12-3

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-65632.json"

Debian:13 / erlang-jose

Package

Name
erlang-jose
Purl
pkg:deb/debian/erlang-jose?arch=source&distro=trixie

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.11.10-1
1.11.12-1
1.11.12-1.1
1.11.12-2~bpo13+1
1.11.12-2
1.11.12-3~bpo13+1
1.11.12-3

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-65632.json"

Debian:14 / erlang-jose

Package

Name
erlang-jose
Purl
pkg:deb/debian/erlang-jose?arch=source&distro=forky

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.11.10-1
1.11.12-1
1.11.12-1.1
1.11.12-2~bpo13+1
1.11.12-2
1.11.12-3~bpo13+1
1.11.12-3

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-65632.json"