CVE-2023-0567: password_verify() always returns true for some invalid hashes

Severity: medium (CVSS 6.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-03-01 · updated 2026-07-19
Weakness: CWE-916

Description

In PHP 8.0.X before 8.0.28, 8.1.X before 8.1.16 and 8.2.X before 8.2.3, password_verify() function may accept some invalid Blowfish hashes as valid. If such invalid hash ever ends up in the password database, it may lead to an application allowing any password for this entry as valid.

Affected products

PHP: from 8.0.0 before 8.0.28; from 8.1.0 before 8.1.16; from 8.2.0 before 8.2.3 — fixed in 8.0.28, 8.1.16, 8.2.3

How to fix

Upgrade to a fixed version: PHP 8.0.28, 8.1.16, 8.2.3. Check the vendor advisory for mitigations.

References

https://bugs.php.net/bug.php?id=81744
https://github.com/php/php-src/security/advisories/GHSA-7fj2-8x79-rjf4
https://bugs.php.net/bug.php?id=81744
https://github.com/php/php-src/security/advisories/GHSA-7fj2-8x79-rjf4
https://security.netapp.com/advisory/ntap-20230331-0008/

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