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perl-5.44.0
⭐ Starred 2013 / MIME::QuotedPrint
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

MIME::QuotedPrint - Encoding and decoding of quoted-printable strings

SYNOPSIS

use MIME::QuotedPrint;

$encoded = encode_qp($decoded);
$decoded = decode_qp($encoded);

DESCRIPTION

This module provides functions to encode and decode strings into and from the quoted-printable encoding specified in RFC 2045 - MIME (Multipurpose Internet Mail Extensions). The quoted-printable encoding is intended to represent data that largely consists of bytes that correspond to printable characters in the ASCII character set. Each non-printable character (as defined by English Americans) is represented by a triplet consisting of the character "=" followed by two hexadecimal digits.

The following functions are provided:

encode_qp( $str)
encode_qp( $str, $eol)
encode_qp( $str, $eol, $binmode )

This function returns an encoded version of the string ($str) given as argument.

The second argument ($eol) is the line-ending sequence to use. It is optional and defaults to "\n". Every occurrence of "\n" is replaced with this string, and it is also used for additional "soft line breaks" to ensure that no line end up longer than 76 characters. Pass it as "\015\012" to produce data suitable for external consumption. The string "\r\n" produces the same result on many platforms, but not all.

The third argument ($binmode) will select binary mode if passed as a TRUE value. In binary mode "\n" will be encoded in the same way as any other non-printable character. This ensures that a decoder will end up with exactly the same string whatever line ending sequence it uses. In general it is preferable to use the base64 encoding for binary data; see MIME::Base64.

An $eol of "" (the empty string) is special. In this case, no "soft line breaks" are introduced and binary mode is effectively enabled so that any "\n" in the original data is encoded as well.

decode_qp( $str )

This function returns the plain text version of the string given as argument. The lines of the result are "\n" terminated, even if the $str argument contains "\r\n" terminated lines.

If you prefer not to import these routines into your namespace, you can call them as:

use MIME::QuotedPrint ();
$encoded = MIME::QuotedPrint::encode($decoded);
$decoded = MIME::QuotedPrint::decode($encoded);

Perl v5.8 and better allow extended Unicode characters in strings. Such strings cannot be encoded directly, as the quoted-printable encoding is only defined for single-byte characters. The solution is to use the Encode module to select the byte encoding you want. For example:

use MIME::QuotedPrint qw(encode_qp);
use Encode qw(encode);

$encoded = encode_qp(encode("UTF-8", "\x{FFFF}\n"));
print $encoded;

COPYRIGHT

Copyright 1995-1997,2002-2004 Gisle Aas.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

MIME::Base64