# CVE-2026-57432: Perl integer overflow and out-of-bounds read in pack and unpack functions

Source: https://junglewise.ai/threats/cve-2026-57432-perl-integer-overflow-and-out-of-bounds-read-in-pack-and-unpack  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-13. Updated: 2026-07-13  
License: CC BY 4.0 with a link back

CVE-2026-57432 · Severity: info · CVSS 0 · Published 2026-07-13

Perl is a widely used programming language for web development, system administration, and network programming. A vulnerability in how Perl handles data formatting (the 'pack' and 'unpack' functions) could allow an attacker to read sensitive information from the computer's memory. This occurs when a program processes a specially crafted data template from an untrusted source, potentially leading to the exposure of private data or credentials.

## Quick answers

**Is CVE-2026-57432 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-57432 being exploited in the wild.

**How severe is CVE-2026-57432?** Informational severity, with a CVSS score of 0, published 13 July 2026.

**Which products and versions are affected?** Perl Foundation Perl through 5.43.10.

**Is there a fix for CVE-2026-57432?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-57432 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-57432?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An integer overflow vulnerability exists in Perl's S_measure_struct function within pp_pack.c. The function fails to validate that the product of an item's size and its repeat count, when added to a running total, does not exceed the limits of a signed SSize_t. A large repeat count in a pack or unpack template can cause the total to wrap to a negative value. Subsequent position codes (@, X, and x) perform signed length comparisons that pass when the length is negative, allowing the buffer pointer to advance out of bounds. An attacker providing a malicious template can trigger an out-of-bounds heap read to leak memory contents. Patches have been developed to implement overflow checks using SSize_t_MAX.

## Affected products

- Perl Foundation Perl through 5.43.10

## Timeline

- 2026-07-13: disclosed
- 2026-07-13: advisory

## References

- [https://cpan.org/modules](https://cpan.org/modules)
- [https://github.com/Perl/perl5/commit/40754edc72dd3e513d758153c0e2f0215897740e.patch](https://github.com/Perl/perl5/commit/40754edc72dd3e513d758153c0e2f0215897740e.patch)
- [https://github.com/Perl/perl5/commit/5f7eb6bbbe0510964e3fb1d6bb691e5445913e55.patch](https://github.com/Perl/perl5/commit/5f7eb6bbbe0510964e3fb1d6bb691e5445913e55.patch)