Signed integer overflow occurs in PHP's metaphone() when a string longer than 2,147,483,647 bytes is passed. The signed int tracking the current position overflows, causing undefined behavior that can lead to an out‑of‑bounds read. This may trigger a segmentation fault or read unrelated memory, resulting in the PHP process crashing and its availability being compromised.

PHP Group: PHP versions 8.2.x prior to 8.2.31, 8.3.x prior to 8.3.31, 8.4.x prior to 8.4.21, and 8.5.x prior to 8.5.6.

The CVSS score of 6.3 indicates moderate severity. EPSS data is unavailable, and the vulnerability is not listed in the CISA KEV catalog. Based on the description, it is inferred that an attacker could trigger the overflow by supplying a very long string to metaphone() in a PHP application. The CVE does not explicitly state how the function is exposed, but it is inferred that applications processing user‑supplied data may provide a network‑exposed entry point, making the attack potentially reachable over the network. The result is a segmentation fault that crashes the PHP process, denying service and impacting availability, though neither confidentiality nor integrity is compromised.