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perl-5.45.1
⭐ Starred 2013 / Porting/corelist-perldelta.pl
Security Advisories (1)
CVE-2026-15534 (2026-08-09)

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.

USAGE

# generate the module changes for the Perl you are currently building
./perl -Ilib Porting/corelist-perldelta.pl

# update the module changes for the Perl you are currently building
./perl -Ilib Porting/corelist-perldelta.pl --mode=update pod/perldelta.pod

# generate a diff between the corelist sections of two perldelta* files:
perl Porting/corelist-perldelta.pl --mode=check 5.017001 5.017002 <perl5172delta.pod

ABOUT

corelist-perldelta.pl is a bit schizophrenic. The part to generate the new Perldelta text does not need Algorithm::Diff, but wants to be run with the freshly built Perl.

The part to check the diff wants to be run with a Perl that has an up-to-date Module::CoreList, but needs the outside Algorithm::Diff.

Ideally, the program will be split into two separate programs, one to generate the text and one to show the diff between the corelist sections of the last perldelta and the next perldelta.

Currently no information about Removed Modules is displayed in any of the modes.