---
id: CVE-2026-77781
title: >-
  Tie::Hash::Regex versions before 2.0.0 for Perl will throw an exception on
  unparseable lookup keys.


  The FETCH, EXISTS and DELETE methods throw an exception when on malformed
  regular expressions.


  Each method falls back to a regex match …
summary: >-
  Tie::Hash::Regex versions before 2.0.0 for Perl will throw an exception on
  unparseable lookup keys.


  The FETCH, EXISTS and DELETE methods throw an exception when on malformed
  regular expressions.


  Each method falls back to a regex match …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-248
published: '2026-08-22'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T19:10:00.173'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77781'
references:
  - url: >-
      https://github.com/davorg-cpan/tie-hash-regex/commit/4239732cb76233543e2ded8ff5e0f238af152e0c.patch
    label: 9b29abf9-4ab0-4765-b253-1875cd9b441e
  - url: 'https://metacpan.org/release/DAVECROSS/Tie-Hash-Regex-2.0.0/source/Changes'
    label: 9b29abf9-4ab0-4765-b253-1875cd9b441e
  - url: 'http://www.openwall.com/lists/oss-security/2026/08/22/2'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00609
epssPercentile: 0.47932
ingestedAt: '2026-10-15T19:25:46.359Z'
---

## Overview

Tie::Hash::Regex versions before 2.0.0 for Perl will throw an exception on unparseable lookup keys.

The FETCH, EXISTS and DELETE methods throw an exception when on malformed regular expressions.

Each method falls back to a regex match when the key is not already stored in the hash, compiling the caller's key with a bare qr// and no eval guard. A key that is not a valid regular expression pattern, such as a single unmatched bracket, dies.

An application that looks up externally supplied strings in a tied hash will die on an invalid key.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.