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Vulnerability · Published Jul 14, 2026 · Assigned by EEF

CVE-2026-55954Missing ID token claim validation in ueberauth_apple allows account takeover

Critical 9.1

In plain English

A critical-severity authentication bypass by spoofing in ueberauth_apple from ueberauth. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities).

Severity (CVSS 4.0)9.1Critical
Exploit odds (30 days)0.5%top 56.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

Authentication Bypass by Spoofing vulnerability in ueberauth ueberauth_apple allows account takeover via unvalidated ID token claims. The Ueberauth.Strategy.Apple.Token.payload/2 function verifies the JWT signature of the callback id_token against Apple's JWKS but does not validate any registered claims. The iss, aud, exp, and iat claims are read from the token and passed on to Ueberauth.Strategy.Apple.handle_callback!/1, which derives the logged-in user's uid and email directly from the unvalidated sub claim. An attacker who obtains any Apple-signed ID token bearing the victim's sub (via a captured expired token, or via an ID token issued to a sibling client in the same Apple developer team) can replay it against the vulnerable callback and be authenticated as the victim. The absent exp check makes stolen tokens usable indefinitely, and the absent aud check enables cross-application account takeover across clients that share an Apple developer team. This issue affects ueberauth_apple: from 0.1.0 before 0.6.2.

Affected products (as reported)

VendorProductVersions
ueberauth ueberauth_apple 0.1.0 – before 0.6.2
ueberauth ueberauth_apple 3908a187d045c75994b62ce340c3aa26bb8976b8 – before 01e2d9c9b3134e1b78633ad82d136d5ff4a61f28

Weakness: CWE-290 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References