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perl-5.43.9
⭐ Starred 2013 / Tie::SubstrHash
Security Advisories (3)
CVE-2026-57432 (2026-07-13)

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.

CVE-2026-13221 (2026-07-13)

Perl versions through 5.43.9 produce silently incorrect regular expression matches when an alternation of more than 65535 fixed string branches is compiled into a trie in Perl_study_chunk. When such branches are combined into a trie, the delta between the first branch and the shared tail is stored in a 16-bit field. A branch count above 65535 overflows the field, and the trie's match decision table is truncated with no warning or error. A pattern of this shape produces false positive matches (matching strings it should not) and false negative matches (failing to match strings it should). When such a pattern gates an access or filtering decision, the result is wrong.

CVE-2026-8376 (2026-05-25)

Perl versions through 5.43.10 have a heap buffer overflow when compiling regular expressions with a repeated fixed string on 32-bit builds. Perl_study_chunk in regcomp_study.c checked the size of the joined substring buffer in characters rather than bytes. For a quantified fixed substring with a large minimum count, the byte length mincount * l could overflow SSize_t, producing an undersized SvGROW allocation; the subsequent copy writes past the end of the buffer. A caller that compiles an attacker-controlled regular expression on a 32-bit perl build triggers a heap buffer overflow at compile time.

NAME

Tie::SubstrHash - Fixed-table-size, fixed-key-length hashing

SYNOPSIS

require Tie::SubstrHash;

tie %myhash, 'Tie::SubstrHash', $key_len, $value_len, $table_size;

DESCRIPTION

The Tie::SubstrHash package provides a hash-table-like interface to an array of determinate size, with constant key size and record size.

Upon tying a new hash to this package, the developer must specify the size of the keys that will be used, the size of the value fields that the keys will index, and the size of the overall table (in terms of key-value pairs, not size in hard memory). These values will not change for the duration of the tied hash. The newly-allocated hash table may now have data stored and retrieved. Efforts to store more than $table_size elements will result in a fatal error, as will efforts to store a value not exactly $value_len characters in length, or reference through a key not exactly $key_len characters in length. While these constraints may seem excessive, the result is a hash table using much less internal memory than an equivalent freely-allocated hash table.

CAVEATS

Because the current implementation uses the table and key sizes for the hashing algorithm, there is no means by which to dynamically change the value of any of the initialization parameters.

The hash does not support exists().