A heap buffer overflow vulnerability was discovered in Perl.

When there are non-ASCII bytes in the left-hand-side of the tr operator, S_do_trans_invmap can overflow the destination pointer d.

   $ perl -e '$_ = "\x{FF}" x 1000000; tr/\xFF/\x{100}/;'
   Segmentation fault (core dumped)

It is believed that this vulnerability can enable Denial of Service and possibly Code Execution attacks on platforms that lack sufficient defenses.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-56406
• https://github.com/Perl/perl5/commit/87f42aa0e0096e9a346c9672aa3a0bd3bef8c1dd.patch
• https://metacpan.org/release/SHAY/perl-5.38.4/changes
• https://metacpan.org/release/SHAY/perl-5.40.2/changes
• http://www.openwall.com/lists/oss-security/2025/04/13/3
• http://www.openwall.com/lists/oss-security/2025/04/13/4
• http://www.openwall.com/lists/oss-security/2025/04/13/5