CVE-2026-57432

CVE-2026-57432 is a high-severity vulnerability rated 8.4/10 on the CVSS scale. Perl versions through 5.43.10 have an integer overflow in S_measure_struct leading to an out-of-bounds heap read in pack and unpack. S_measure_struct adds each item's size times its repeat count to a running total with no overflow check, so a large repeat count in a pack or unpack template wraps the signed SSize_t total negative. The @, X, and x position codes then guard their moves with a signed length comparison that passes when the length is negative, advancing the buffer pointer out of bounds. A template derived from untrusted input can read heap memory past the buffer and return it to the caller.. EPSS estimates a 0.21% chance of exploitation in the next 30 days.