Some invalid Blowfish ($2y$) hashes are treated as valid, so any password may match such a stored hash.
Affected versions
| Branch | Affected | Fixed in |
|---|---|---|
| PHP 8.2 | < 8.2.3 | 8.2.3 |
| PHP 8.1 | < 8.1.16 | 8.1.16 |
| PHP 8.0 | < 8.0.28 | 8.0.28 |
Older branches: not assessed
Exploitation conditions
No special conditions are documented.
Remediation
Upgrade to 8.0.28, 8.1.16, 8.2.3 or a later release of your branch. If your branch is end-of-life, move to a supported branch. Distribution packages may carry a backported fix under an older version number; confirm with your vendor's security tracker.
A version number alone cannot prove patch status. Linux distributions and hosting providers often backport security fixes without changing the version. Check your vendor’s changelog.
Severity scores
| CVSS | Source | Vector |
|---|---|---|
| 6.2 v3.1 | NVD | — |
References
Data provenance
Secondary sources · pending primary verificationLast reviewed: Oct 24, 2026 · Source
Notes: Distributions rate this between 6.2 and 7.7.