REDHAT-BUG-2509256: High severity PHP PHP vulnerability

Published Jul 30, 2026
·
Updated

Attacker-provided inputs to bccomp() could lead to an out-of-bounds write with stack and heap corruption in PHP versions from 8.4. before 8.4.24 and from 8.5. before 8.5.9.

Affected Software

2 affected components
PHP PHP>8.4<=8.4.24
PHP PHP>8.5<=8.5.9

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade PHP to a version that resolves this vulnerability.

    Fixed in 8.4.24
  2. Upgrade

    Upgrade PHP to a version that resolves this vulnerability.

    Fixed in 8.5.9

Event History

Jul 30, 2026
Data Sourced
via Red Hat·12:01 PM
DescriptionSeverityAffected Software

Frequently Asked Questions

1

Which PHP deployments are affected?

PHP versions in the 8.4 branch before 8.4.24 and in the 8.5 branch before 8.5.9 are affected. The provided information does not identify any affected versions outside those ranges.

2

What does an attacker need to exploit this issue?

An attacker needs to be able to provide input that reaches the bccomp() function. The issue is triggered by attacker-provided inputs and can result in an out-of-bounds write with stack and heap corruption.

3

How can I determine whether my environment needs remediation?

Check the installed PHP version and whether untrusted input can be passed to bccomp(). Systems running PHP 8.4 earlier than 8.4.24 or PHP 8.5 earlier than 8.5.9 should be treated as affected when such input is reachable.

Contact

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