Heap-based Buffer Overflow Affecting php package, versions [,8.2.34)[8.3.0RC1,8.3.35)[8.4.0RC1,8.4.26)[8.5.0RC1,8.5.11)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
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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Start learning- Snyk IDSNYK-UNMANAGED-PHP-20158768
- published27 Sept 2026
- disclosed25 Sept 2026
- creditMohamed Sayed
Introduced: 25 Sep 2026
NewCVE-2026-91767 (opens in a new tab)How to fix?
Upgrade php to version 8.2.34, 8.3.35, 8.4.26, 8.5.11 or higher.
Overview
Affected versions of this package are vulnerable to Heap-based Buffer Overflow in php_openssl_matches_wildcard_name() in ext/openssl/xp_ssl.c, where the guard before the memchr() scan accounts only for the suffix length, so the size_t expression subject_len - suffix_len - prefix_len wraps to SIZE_MAX whenever the literal characters around the wildcard outnumber the hostname being verified. An attacker can crash the process by presenting a TLS certificate whose wildcard name has that shape, for example a CN of aaa*aa verified against the hostname aaaa, which makes the scan run unbounded past the end of the heap allocation. This requires either control of the server the client connects to or a certificate trusted through the CA in use, and the read halts at the first . byte, so no heap content reaches the attacker.