CVE-2026-17544: Out-of-bounds write in bccomp() via crafted operand and scale
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.
Other sources
Fixed (Out-of-bounds write in bccomp()). (CVE-2026-17544)
— PHP
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 8.4.24 - Upgrade
Upgrade
PHPto a version that resolves this vulnerability.Fixed in 8.4.24 - Upgrade
Upgrade
PHPto a version that resolves this vulnerability.Fixed in 8.5.9
Event History
Frequently Asked Questions
What is the severity of CVE-2026-17544?
CVE-2026-17544 has a severity rating of high with a CVSS score of 8.1.
How do I fix CVE-2026-17544?
To fix CVE-2026-17544, update PHP to version 8.4.24 or higher, or version 8.5.9 or higher.
What causes the vulnerability described in CVE-2026-17544?
CVE-2026-17544 is caused by attacker-provided inputs to the bccomp() function leading to out-of-bounds write vulnerabilities.
Which PHP versions are affected by CVE-2026-17544?
PHP versions 8.4.* before 8.4.24 and 8.5.* before 8.5.9 are affected by CVE-2026-17544.
What are the potential impacts of CVE-2026-17544?
CVE-2026-17544 can lead to stack and heap corruption, potentially allowing an attacker to execute arbitrary code.