---
title: "CVE-2026-96760: Authlib: empty signatures validation in JWS JSON deserialization"
url: https://erroneo.us/security/cve/CVE-2026-96760/
description: "CVE-2026-96760 (authlib (PyPI)): Authlib (v1.7.2 and below) contains a signature verification bypass vulnerability. The JsonWebSignature.deserializejson()…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-09-28
date_modified: 2026-10-27
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-96760"
kev: false
cvss: 9.8
epss: 0.00433
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-96760: Authlib: empty signatures validation in JWS JSON deserialization

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.4% , percentile 38: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 38% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes authlib (PyPI) <= 1.8.0, fixed in 1.9.0 . Check your lockfile, including transitive dependencies.

## What it is

Authlib (v1.7.2 and below) contains a signature verification bypass vulnerability. The JsonWebSignature.deserializejson() method accepts a JSON Serialization JWS object and returns the payload as successfully verified without checking for a signature and without requiring a cryptographic key.

## Affected packages

- PyPI `authlib` <= 1.8.0 → fixed: 1.9.0

## Affected products (CVE record)

- Authlib Authlib: 1.7.2

## Severity

- CISA-ADP CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-11-05): 0.43% probability of exploitation activity in the next 30 days; percentile 38.

## Sources

- [GitHub Advisory GHSA-6v38-4h7w-rj9h](https://github.com/advisories/GHSA-6v38-4h7w-rj9h)
- [CVE.org record CVE-2026-96760](https://www.cve.org/CVERecord?id=CVE-2026-96760)
- [NVD entry CVE-2026-96760](https://nvd.nist.gov/vuln/detail/CVE-2026-96760)
- [github.com](https://github.com/authlib/authlib)
- [kb.cert.org](https://kb.cert.org/vuls/id/762428)
- [kb.cert.org](https://www.kb.cert.org/vuls/id/762428)
- [github.com](https://github.com/authlib/authlib/security/advisories/GHSA-6v38-4h7w-rj9h)
- [github.com](https://github.com/authlib/authlib/pull/938)
- [github.com](https://github.com/authlib/authlib/commit/6c11a02da8730914cea08ec195f1108a40dc6733)
- [github.com](https://github.com/authlib/authlib/releases/tag/v1.9.0)

---
Source page: https://erroneo.us/security/cve/CVE-2026-96760/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt