---
title: "CVE-2026-4176\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2026-4176?format=md
keywords: index, follow
---

# CVE-2026-4176

Publication date 29 March 2026

Last updated 1 April 2026

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**9.8 · Critical**

[Score breakdown](https://ubuntu.com/security/CVE-2026-4176?format=md#impact-score)

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## Description

Perl versions from 5.9.4 before 5.40.4-RC1, from 5.41.0 before 5.42.2-RC1,
from 5.43.0 before 5.43.9 contain a vulnerable version of
Compress::Raw::Zlib.
Compress::Raw::Zlib is included in the Perl package as a dual-life core
module, and is vulnerable to CVE-2026-3381 due to a vendored version of
zlib which has several vulnerabilities, including CVE-2026-27171. The
bundled Compress::Raw::Zlib was updated to version 2.221 in Perl blead
commit c75ae9cc164205e1b6d6dbd57bd2c65c8593fe94.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| perl | 26.04 LTS resolute | Not affected |
| 25.10 questing | Not affected |
| 24.04 LTS noble | Not affected |
| 22.04 LTS jammy | Not affected |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Needs evaluation |
| 14.04 LTS trusty | Needs evaluation |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

9.8 · Critical

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | High |
  | Integrity impact | High |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 9.8 · Critical |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-4176)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-4176)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-4176)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-4176)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-4176>
* <https://lists.security.metacpan.org/cve-announce/msg/38393284/>
* <https://github.com/Perl/perl5/commit/c75ae9cc164205e1b6d6dbd57bd2c65c8593fe94>
* <https://lists.security.metacpan.org/cve-announce/msg/37638919/>
* <https://metacpan.org/release/PMQS/Compress-Raw-Zlib-2.221/source/Changes>
* <https://metacpan.org/release/SHAY/perl-5.40.4/changes>
* <https://metacpan.org/release/SHAY/perl-5.42.2/changes>
* <https://www.cve.org/CVERecord?id=CVE-2026-3381>
* <http://www.openwall.com/lists/oss-security/2026/03/30/2>