---
title: "CVE-2026-5673\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-2026-5673?format=md
keywords: index, follow
---

# CVE-2026-5673

Publication date 6 April 2026

Last updated 13 May 2026

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**5.6 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2026-5673?format=md#impact-score)

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## Description

A flaw was found in libtheora. This heap-based out-of-bounds read
vulnerability exists within the AVI (Audio Video Interleave) parser,
specifically in the avi\_parse\_input\_file() function. A local attacker could
exploit this by tricking a user into opening a specially crafted AVI file
containing a truncated header sub-chunk. This could lead to a
denial-of-service (application crash) or potentially leak sensitive
information from the heap.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2026-5673?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| asc | 26.04 LTS resolute | Vulnerable, fix deferred |
| 25.10 questing | Ignored end of life, was deferred [2026-04-10] |
| 24.04 LTS noble | Vulnerable, fix deferred |
| 22.04 LTS jammy | Vulnerable, fix deferred |
| 20.04 LTS focal | Vulnerable, fix deferred |
| 18.04 LTS bionic | Vulnerable, fix deferred |
| 16.04 LTS xenial | Vulnerable, fix deferred |
| mkvtoolnix | 26.04 LTS resolute | Vulnerable, fix deferred |
| 25.10 questing | Ignored end of life, was deferred [2026-04-10] |
| 24.04 LTS noble | Vulnerable, fix deferred |
| 22.04 LTS jammy | Vulnerable, fix deferred |
| 20.04 LTS focal | Vulnerable, fix deferred |
| 18.04 LTS bionic | Vulnerable, fix deferred |
| 16.04 LTS xenial | Vulnerable, fix deferred |
| ogmrip | 26.04 LTS resolute | Vulnerable, fix deferred |
| 25.10 questing | Ignored end of life, was deferred [2026-04-10] |
| 24.04 LTS noble | Not in release |
| 22.04 LTS jammy | Vulnerable, fix deferred |
| 20.04 LTS focal | Vulnerable, fix deferred |
| 18.04 LTS bionic | Vulnerable, fix deferred |
| 16.04 LTS xenial | Vulnerable, fix deferred |
| libtheora | 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 | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2026-5673?format=md#patch-details)

## Notes

---

### [rodrigo-zaiden](https://launchpad.net/~rodrigo-zaiden)

bug seems to be in avilib, which is also included
in ogmrip, mkvtoolnix, and asc packages, which could be also
affected if there is no prevetion code before calling avilib.

---

### [mdeslaur](https://launchpad.net/~mdeslaur)

The vulnerable file in the theora package is in the win32
directory and is not built in Ubuntu packages.

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| libtheora | * Upstream:   [fb92ede](https://github.com/xiph/theora/commit/fb92ede9ba5162d0b8134cd1ff57751df6f3dbe6) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

5.6 · Medium

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 5.6 · Medium |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-5673)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-5673)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-5673)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-5673)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-5673>
* <https://access.redhat.com/security/cve/CVE-2026-5673>