Critical severity · published Jul 30, 2026
CVE-2026-17544
Out-of-bounds write in bccomp() via crafted operand and scale
9.8
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PH
PHP · PHP
8.4.* before 8.4.24; 8.5.* before 8.5.9 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-17544
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-17544
Vendor Advisory
https://github.com/php/php-src/security/advisories/GHSA-x692-q9x7-8c3f
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