Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Packagist package causal/oidc versions >=3.0.0 and <4.0.0 are vulnerable to account takeover through the account linking logic, a pre-hijacking attack. An attacker must know the user's email address, register a public frontend account with that address before the user's first OIDC login, and have the identity provider return that email, after which they can take over the user's account. Upgrade to version 4.0.0.
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 |
|---|---|---|---|---|
| 4.2 | Medium | 3.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N/E:F/RL:O/RC:C | CNA (mitre) |
- CISA KEV Not listed.
- EPSS 0.0018, the 7th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:27 UTC First seen by agentprime
- 31 Oct 2026, 14:27 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-hj78-p4h7-m5fv
- OSV: GHSA-hj78-p4h7-m5fv
- nvd.nist.gov/vuln/detail/CVE-2025-24856
- github.com/xperseguers/t3ext-oidc/commit/877e09f6faf4c87bbb41233112ec7e30d3c902b3
- github.com/FriendsOfPHP/security-advisories/blob/master/causal/oidc/CVE-2025-24856.yaml
- typo3.org/security/advisory/typo3-ext-sa-2025-001