GHSA-7wc2-qxgw-g8gg: authlib (CVE-2026-28802)

Package	Ecosystem	Affected	Fixed in
authlib	PyPI	>=1.6.5, <1.6.7	1.6.7

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Authlib versions 1.6.5 up to but not including 1.6.7 can accept JSON Web Tokens that use the "alg: none" header with an empty signature, so signature verification appears to be skipped. An attacker who can submit a crafted token to an application using this library could forge tokens and gain unauthorized access, such as authentication bypass or privilege escalation. Upgrade to Authlib 1.6.7. The source gives few details on the exact conditions under which the bypass applies.

Written 5 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
7.7	High	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0054, the 45th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:34 UTC First seen by agentprime
31 Oct 2026, 14:34 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.