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🛡️ CVE-2026-0877 on Ubuntu — mozjs102

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

Distribution advisory

This page covers CVE-2026-0877 as tracked by Ubuntu, for the package mozjs102. The fix is available in version 1:140.7.1+build1-0ubuntu0.22.04.1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: Required — someone has to click, open or visit something.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

UBUNTU-CVE-2026-0877 is classified as CWE-693: Protection Mechanism Failure. A protection exists but does not cover the case at hand, so it can be worked around.

Affected software

UBUNTU-CVE-2026-0877 is recorded against 8 packages.

  • mozjs102
  • mozjs115
  • mozjs38
  • mozjs52
  • mozjs68
  • mozjs78
  • mozjs91
  • thunderbird (fixed in 1:140.7.1+build1-0ubuntu0.22.04.1)

Timeline and source

Published on 13 January 2026 and last revised on 29 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
www.mozilla.org (Report)
www.mozilla.org (Report)
bugzilla.mozilla.org (Report)
www.mozilla.org (Report)
www.mozilla.org (Report)
www.mozilla.org (Report)
ubuntu.com (Advisory)

Same weakness in other software

These advisories are the same class of weakness (CWE-693: Protection Mechanism Failure) in other software:

CVE-2026-0877 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-01-13
Updated 2026-08-20
Modified 2026-07-29
Fix URL N/A

Affected Packages

Software From version Fixed in
mozjs102 — —
mozjs115 — —
mozjs38 — —
mozjs52 — —
mozjs68 — —
mozjs78 — —
mozjs91 — —
thunderbird — 1:140.7.1+build1-0ubuntu0.22.04.1

Site Security Check

Is mozjs102 part of your stack?

UBUNTU-CVE-2026-0877 is rated CVSS 8.1 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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