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perl-5.44.0
⭐ Starred 2013 / encguess
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.

NAME

encguess - guess character encodings of files

VERSION

$Id: encguess,v 0.4 2023/11/10 01:10:50 dankogai Exp $

SYNOPSIS

encguess [switches] filename...

SWITCHES

-h

show this message and exit.

-s

specify a list of "suspect encoding types" to test, separated by either : or ,

-S

output a list of all acceptable encoding types that can be used with the -s param

-u

suppress display of unidentified types

EXAMPLES:

  • Guess encoding of a file named test.txt, using only the default suspect types.

    encguess test.txt

  • Guess the encoding type of a file named test.txt, using the suspect types euc-jp,shiftjis,7bit-jis.

    encguess -s euc-jp,shiftjis,7bit-jis test.txt
encguess -s euc-jp:shiftjis:7bit-jis test.txt

  • Guess the encoding type of several files, do not display results for unidentified files.

    encguess -us euc-jp,shiftjis,7bit-jis test*.txt

DESCRIPTION

The encoding identification is done by checking one encoding type at a time until all but the right type are eliminated. The set of encoding types to try is defined by the -s parameter and defaults to ascii, utf8 and UTF-16/32 with BOM. This can be overridden by passing one or more encoding types via the -s parameter. If you need to pass in multiple suspect encoding types, use a quoted string with the a space separating each value.

SEE ALSO

Encode::Guess, Encode::Detect

LICENSE AND COPYRIGHT

Copyright 2015 Michael LaGrasta and Dan Kogai.

This program is free software; you can redistribute it and/or modify it under the terms of the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0