Out-of-bounds Write Affecting php package, versions [,8.4.24)[8.5.0,8.5.9)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UNMANAGED-PHP-19477231
- published1 Sept 2026
- disclosed30 Jul 2026
- creditrecepasan
Introduced: 30 Jul 2026
CVE-2026-17544 (opens in a new tab)How to fix?
Upgrade php to version 8.4.24, 8.5.9 or higher.
Overview
Affected versions of this package are vulnerable to Out-of-bounds Write through bc_str2num() in ext/bcmath/libbcmath/src/str2num.c. An attacker can corrupt stack or heap memory by calling bccomp() with a crafted operand and scale that truncates a fraction and then trims trailing zeros, causing the code to copy more digits than were reserved. When the vulnerable path processes small numbers in BCMath’s stack-allocated arena, the write reaches stack memory; otherwise it can overflow a heap buffer. This can crash PHP or enable memory corruption during comparison of attacker-controlled numeric strings.