CVE-2026-15534
MediumCVSS 5.7Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
A vulnerability in Perl's regular expression engine (up to version 5.45.1) causes out-of-bounds reads and writes during pattern matching. The issue stems from an integer overflow in the superlinear cache counter, leading to undersized allocation and subsequent out-of-bounds access.
Risk Assessment
An attacker can cause a process crash or heap memory corruption, potentially enabling arbitrary code execution or compromising system integrity.
Recommendation
Immediately upgrade Perl to a version newer than 5.45.1 if available, and restrict processing of untrusted large inputs in regular expressions.
Original NVD description (English source)
Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch. The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it. A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.