# CVE-2026-114615: Authlib incomplete algorithm-confusion fix permits HMAC forgery with prefixed public keys


- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 22 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-114615, ECHO-47bf-b555-f683, GHSA-7vr2-2fgp-9w7p, MINI-fcx9-3vf9-f9qm, UBUNTU-CVE-2026-114615

## What is CVE-2026-114615?

CVE-2026-114615 is a high-severity vulnerability in authlib, published on 22 Oct 2026. 

### Official 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.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature), CWE-184 (Incomplete List of Disallowed Inputs)

## Which versions are affected by CVE-2026-114615?

2 open source packages ship an affected version, including authlib. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `authlib` | PyPI | From 1.3.1 | 1.9.0 |
| `authlib` | PyPI | From 1.3.1 | 1.9.0 |

Products: Authlib Authlib.

## How do I fix CVE-2026-114615?

Upgrade authlib to 1.9.0 or later.

## Is CVE-2026-114615 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-114615 exists.

## Other vulnerabilities in authlib

- [CVE-2026-27962](https://insights.sbomify.com/CVE-2026-27962/): Authlib JWS JWK Header Injection: Signature Verification Bypass (critical 9.1)
- [CVE-2026-28490](https://insights.sbomify.com/CVE-2026-28490/): Authlib Vulnerable to JWE RSA1_5 Bleichenbacher Padding Oracle (high 8.3)
- [CVE-2026-28498](https://insights.sbomify.com/CVE-2026-28498/): Authlib: Fail-Open Cryptographic Verification in OIDC Hash Binding (high 8.2)
- [CVE-2026-28802](https://insights.sbomify.com/CVE-2026-28802/): Authlib: Setting `alg: none` and a blank signature appears to bypass signature verification (high 7.7)
- [CVE-2025-61920](https://insights.sbomify.com/CVE-2025-61920/): Authlib is vulnerable to Denial of Service via Oversized JOSE Segments (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-114615 and fix it if it is affected.

What it is: CVE-2026-114615 is a high-severity vulnerability in authlib, published on 22 Oct 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-114615 exists.

Affected packages and fixed versions:
- authlib (PyPI): affected from 1.3.1; fixed in 1.9.0
- authlib (PyPI): affected from 1.3.1; fixed in 1.9.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-114615/ (Markdown: https://insights.sbomify.com/CVE-2026-114615/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-114615
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-114615
- OSV: https://osv.dev/vulnerability/CVE-2026-114615

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-114615/
Summaries are generated and may contain mistakes; the official description above is the record.