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perl-5.45.1
⭐ Starred 2013 / OS2::ExtAttr
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

OS2::ExtAttr - Perl access to extended attributes.

SYNOPSIS

use OS2::ExtAttr;
tie %ea, 'OS2::ExtAttr', 'my.file';
print $ea{eaname};
$ea{myfield} = 'value';

untie %ea;

DESCRIPTION

The package provides low-level and high-level interface to Extended Attributes under OS/2.

High-level interface: tie

The only argument of tie() is a file name, or an open file handle.

Note that all the changes of the tied hash happen in core, to propagate it to disk the tied hash should be untie()ed or should go out of scope. Alternatively, one may use the low-level update method on the corresponding object. Example:

tied(%hash)->update;

Note also that setting/getting EA flag is not supported by the high-level interface, one should use the low-level interface instead. To use it on a tied hash one needs undocumented way to find eas give the tied hash.

Low-level interface

Two low-level methods are supported by the objects: copy() and update(). The copy() takes one argument: the name of a file to copy the attributes to, or an opened file handle. update() takes no arguments, and is discussed above.

Three convenience functions are provided:

value($eas, $key)
add($eas, $key, $value [, $flag])
replace($eas, $key, $value [, $flag])

The default value for flag is 0.

In addition, all the _ea_* and _ead_* functions defined in EMX library are supported, with leading _ea and _ead stripped.

AUTHOR

Ilya Zakharevich, ilya@math.ohio-state.edu

SEE ALSO

perl(1).