Vulnerability · Published Jul 30, 2026 · Assigned by php
CVE-2026-17544Out-of-bounds write in bccomp() via crafted operand and scale
High 8.1
In plain English
A high-severity out-of-bounds write in PHP from PHP Group. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)8.1High
Exploit odds (30 days)0.4%top 63.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | php8.4 | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-bcmath | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-cli | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-common | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-dba | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-dbg | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-devel | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-embedded | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-enchant | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-ffi | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-fpm | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-gd | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-gmp | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-intl | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-ldap | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-mbstring | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-mysqlnd | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-odbc | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-opcache | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-pdo | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-pgsql | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-process | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-snmp | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-soap | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| AlmaLinux:10 | php8.4-xml | 8.4.24-1.el10_2 | ALSA-2026:56969 |
| Alpine:v3.22 | php84 | 8.4.27-r0 | ALPINE-CVE-2026-17544 |
| Alpine:v3.23 | php84 | 8.4.27-r0 | ALPINE-CVE-2026-17544 |
| Alpine:v3.24 | php84 | 8.4.24-r0 | ALPINE-CVE-2026-17544 |
| Alpine:v3.23 | php85 | 8.5.12-r0 | ALPINE-CVE-2026-17544 |
| Alpine:v3.24 | php85 | 8.5.9-r0 | ALPINE-CVE-2026-17544 |
| Debian:13 | php8.4 | 8.4.24-1~deb13u1 | DEBIAN-CVE-2026-17544 |
| Debian:14 | php8.4 | 8.4.24-1 | DEBIAN-CVE-2026-17544 |
| Rocky Linux:10 | php8.4 | 0:8.4.24-1.el10_2 | RLSA-2026:56969 |
| Ubuntu:22.04:LTS | php8.1 | 8.1.2-1ubuntu2.26 | USN-8743-1 |
| Ubuntu:24.04:LTS | php8.3 | 8.3.6-0ubuntu0.24.04.11 | USN-8743-1 |
| Ubuntu:26.04:LTS | php8.5 | 8.5.4-0ubuntu1.3 | UBUNTU-CVE-2026-17544 |
| Ubuntu:26.04:LTS | php8.5 | 8.5.4-0ubuntu1.3 | USN-8743-1 |
Affected products (as reported)
Weakness: CWE-787 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/AU:N