---
title: "CVE-2026-1979\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-2026-1979?format=md
keywords: index, follow
---

# CVE-2026-1979

Publication date 6 February 2026

Last updated 11 September 2026

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**5.3 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2026-1979?format=md#impact-score)

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## Description

A flaw has been found in mruby up to 3.4.0. This affects the function
mrb\_vm\_exec of the file src/vm.c of the component JMPNOT-to-JMPIF
Optimization. Executing a manipulation can lead to use after free. The
attack needs to be launched locally. The exploit has been published and may
be used. This patch is called e50f15c1c6e131fa7934355eb02b8173b13df415. It
is advisable to implement a patch to correct this issue.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| mruby | 26.04 LTS resolute | Needs evaluation |
| 25.10 questing | Ignored end of life, was needs-triage |
| 24.04 LTS noble | Needs evaluation |
| 22.04 LTS jammy | Needs evaluation |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | 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 v4.0

[CVSS v4.0](https://ubuntu.com/security/CVE-2026-1979?format=md)
[CVSS v3.0](https://ubuntu.com/security/CVE-2026-1979?format=md)

**Base score**

1.9 · Low

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Local |
  | Attack complexity | Low |
  | Attack requirements | None |
  | Privileges required | Low |
  | User interaction | None |
  | Vulnerable system - Confidentiality impact | Low |
  | Vulnerable system - Integrity impact | Low |
  | Vulnerable system - Availability impact | Low |
  | Subsequent system - Confidentiality impact | None |
  | Subsequent system - Integrity impact | None |
  | Subsequent system - Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 1.9 · Low |
  | Base + Threat score | - |
  | Base + Environmental score | - |
  | Base + Threat + Environmental score | - |

**Vector:** CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-1979)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-1979)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-1979)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-1979)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-1979>
* <https://github.com/mruby/mruby/issues/6701>
* <https://github.com/sysfce2/mruby/commit/e50f15c1c6e131fa7934355eb02b8173b13df415>
* <https://github.com/mruby/mruby/>
* <https://github.com/mruby/mruby/issues/6701#issue-3802609843>
* <https://vuldb.com/?ctiid.344501>
* <https://vuldb.com/?id.344501>
* <https://vuldb.com/?submit.743377>