High · CVSS 7.4CVE-2026-114615

Authlib incomplete algorithm-confusion fix permits HMAC forgery with prefixed public keysCVE-2026-114615

Answer in brief

CVE-2026-114615 records a High severity (CVSS 7.4) vulnerability in Authlib incomplete algorithm-confusion fix permits HMAC forgery with prefixed public keys. The current sources do not mark it as known exploited. The current feed maps authlib/authlib (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 22, 2026Updated Oct 22, 2026Source checked Oct 22, 2026First seen by HOL Oct 22, 2026Material review Oct 22, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.4
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 7.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps authlib/authlib (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
authlib/authlibgeneric	>=1.3.1 <1.9.0	1.9.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for authlib/authlib.
Review the reported fix. Update authlib/authlib to 1.9.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 22, 2026

Sources and claim methodology

Upstream source description

Authlib is a Python library which builds OAuth and OpenID Connect servers. From 1.3.1 until 1.9.0, OctKey.import_key() checks asymmetric-key markers only at byte zero while Authlib's PEM loaders accept leading whitespace, comments, or a byte-order mark. In deployments that use the documented mixed algorithm registry and already configure verification with PEM or certificate bytes containing such a prefix, an unauthenticated attacker who knows those same public-key bytes can use them as an HMAC secret and forge HS256 tokens with arbitrary identity or authorization claims. This is a bypass of the remediation for CVE-2024-37568. The module-level jwt object reaches OctKey.import_key() in authlib/jose/rfc7518/oct_key.py, where POSSIBLE_UNSAFE_KEYS fails to identify prefixed asymmetric key material. This issue is fixed in version 1.9.0.

Quoted source text, attributed separately from HOL analysis.