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CVE-2026-49265

6.8 Moyenne

Publiée le 13/10/2026 à 18:17 · Modifiée le 16/10/2026 à 22:04 · Analyse NVD reportée · Source : security-advisories@github.com

Description

OAuthLib is an implementation of the OAuth request-signing logic for Python 3.6+. From 3.0.0 until 4.0.0, OAuthLib's PKCE checks in oauthlib/oauth2/rfc6749/grant_types/authorization_code.py compare attacker-supplied code_verifier values with stored challenges using ordinary string equality in code_challenge_method_plain and code_challenge_method_s256. Because the comparison can return after a length difference or the first mismatching character, repeated token endpoint measurements can reveal common-prefix timing information that could potentially allow recovery of the code_verifier, unauthorized access-token acquisition, and account takeover. Practical exploitation requires an intercepted, single-use authorization code and enough measurements to overcome real-world network noise; the local timing benchmark does not establish practical remote account takeover, so the weakness remains a defense-in-depth concern. This issue is fixed in version 4.0.0.

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Produits concernés

Scores CVSS

VersionScoreSourceVecteur
3.1 6.8 Moyenne security-advisories@github.com CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Faiblesses (CWE)

Références

Ailleurs