Missing ID token claim validation in ueberauth_apple allows account takeover

Weakness Type (CWE)

CWE-290 — CWE-290 Authentication Bypass by Spoofing

CAPEC

CAPEC-60 — CAPEC-60 Reusing Session IDs (aka Session Replay)

CVSS 4.0 Score

9.1

CRITICAL

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

Vulnerability 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

`pkg:hex/ueberauth_apple`

Module	Source File	Routine
`Ueberauth.Strategy.Apple`	`lib/ueberauth/strategy/apple.ex`	`Ueberauth.Strategy.Apple.handle_callback!/1`
`Ueberauth.Strategy.Apple.Token`	`lib/ueberauth/strategy/apple/token.ex`	`Ueberauth.Strategy.Apple.Token.payload/2`

Status	Type	Version	Changes / Fixed in
affected	semver ^ⓘ	`0.1.0`	< `0.6.2`

`pkg:github/ueberauth/ueberauth_apple`

Module	Source File	Routine
`Ueberauth.Strategy.Apple`	`lib/ueberauth/strategy/apple.ex`	`Ueberauth.Strategy.Apple.handle_callback!/1`
`Ueberauth.Strategy.Apple.Token`	`lib/ueberauth/strategy/apple/token.ex`	`Ueberauth.Strategy.Apple.Token.payload/2`

Status	Type	Version	Changes / Fixed in
affected	git ^ⓘ	`3908a187d0`	< `01e2d9c9b3`

References

https://github.com/ueberauth/ueberauth_apple/security/advisories/GHSA-pxx8-68pc-p9mr vendor-advisory related
https://osv.dev/vulnerability/EEF-CVE-2026-55954 related
https://github.com/ueberauth/ueberauth_apple/commit/01e2d9c9b3134e1b78633ad82d136d5ff4a61f28 patch

Credits

Finder: 0xRenSec
Remediation developer: AJ Foster
Analyst: Jonatan Männchen / EEF

CVE record as JSON: GET /cves/CVE-2026-55954.json
OSV record as JSON: GET /osv/EEF-CVE-2026-55954.json