GHSA-hj66-6f7g-4r5v: oauthlib (CVE-2026-49264)

Package	Ecosystem	Affected	Fixed in
oauthlib	PyPI	>=0.6.1, <4.0.0	4.0.0

Machine-written summary

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

Oauthlib versions from 0.6.1 up to but not including 4.0.0 are affected when the RevocationEndpoint is created with enable_jsonp=True, because the user-supplied callback parameter is reflected into the JavaScript response without validation. An attacker who can influence that parameter can make the response contain arbitrary JavaScript, which runs in the origin of any page that loads the endpoint as JSONP. Upgrade to oauthlib 4.0.0 or later. The source does not list a workaround other than leaving enable_jsonp disabled, which is the default.

Written 1 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
6.1	Medium	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0023, the 14th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:08 UTC First seen by agentprime
31 Oct 2026, 14:08 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.