Vulnerability · Published Oct 13, 2026 · Assigned by GitHub_M
CVE-2026-49264OAuthLib: Unsafe JSONP callback injection in RevocationEndpoint allows arbitrary JavaScript response generation
Medium 6.1
In plain English
A medium-severity cross-site scripting in oauthlib from oauthlib. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 14% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
OAuthLib is an implementation of the OAuth request-signing logic for Python 3.6+. From 0.6.1 until 4.0.0, OAuthLib's RevocationEndpoint in oauthlib/oauth2/rfc6749/endpoints/revocation.py reflects an unvalidated callback request parameter into success and error response bodies when enable_jsonp=True. The callback can come from the query string or request body and is used without restricting it to a legal JavaScript function name. A browser application that loads the revocation response as trusted JSONP and permits attacker influence over callback can therefore execute attacker-controlled JavaScript in the including application's origin, with access to its DOM and script-accessible data. The feature is disabled by default, so only deployments that explicitly enable JSONP are affected. This issue is fixed in version 4.0.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-oauthlib | no fix listed | DEBIAN-CVE-2026-49264 |
| Debian:13 | python-oauthlib | no fix listed | DEBIAN-CVE-2026-49264 |
| Debian:14 | python-oauthlib | no fix listed | DEBIAN-CVE-2026-49264 |
| PyPI | oauthlib | 4.0.0 | GHSA-hj66-6f7g-4r5v |
| PyPI | oauthlib | 4.0.0 | PYSEC-2026-4113 |
| Ubuntu:22.04:LTS | python-oauthlib | no fix listed | UBUNTU-CVE-2026-49264 |
| Ubuntu:24.04:LTS | python-oauthlib | no fix listed | UBUNTU-CVE-2026-49264 |
| Ubuntu:26.04:LTS | python-oauthlib | no fix listed | UBUNTU-CVE-2026-49264 |
| Ubuntu:26.10 | python-oauthlib | no fix listed | UBUNTU-CVE-2026-49264 |
Affected products (as reported)
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
References
- https://github.com/oauthlib/oauthlib/security/advisories/GHSA-hj66-6f7g-4r5v x_refsource_CONFIRM
- https://github.com/oauthlib/oauthlib/pull/951 x_refsource_MISC
- https://github.com/oauthlib/oauthlib/commit/c888359f3c42bec235b2c5caab2069c9ed62457c x_refsource_MISC
- https://github.com/oauthlib/oauthlib/releases/tag/v4.0.0 x_refsource_MISC