🛡️ CVE-2025-5271 on Ubuntu — mozjs102

Distribution advisory

This page covers CVE-2025-5271 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 low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity low, availability none.

CVSS metrics in full

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

• Attack vector: Network — reachable from anywhere that can route to the service.
• Attack complexity: Low — the attack works reliably, with no preparation.
• Privileges required: None — an unauthenticated stranger can try it.
• User interaction: None — nobody has to be tricked into anything.
• Scope: Unchanged — the damage stays inside the vulnerable component.
• Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
• Integrity impact: Low — limited, and the attacker does not choose what is affected.
• Availability impact: None.

Weakness class

UBUNTU-CVE-2025-5271 is classified as CWE-116: Improper Encoding or Escaping of Output. Output is emitted without encoding it for the context it lands in, so data is interpreted as markup or code.

Affected software

UBUNTU-CVE-2025-5271 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 27 May 2025 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)
bugzilla.mozilla.org (Report)
www.mozilla.org (Report)
ubuntu.com (Advisory)

Same weakness in other software

These advisories are the same class of weakness (CWE-116: Improper Encoding or Escaping of Output) in other software:

• CVE-2026-54133 (9.5 Critical, published 18 Aug 2026)
• CVE-2026-66486 (published 10 Aug 2026)
• CVE-2026-70609 (published 5 Aug 2026)
• CVE-2026-54364 (6.5 Medium, published 30 Jul 2026)
• CVE-2026-50642 (published 29 Jul 2026)
• CVE-2026-54705 (6.3 Medium, published 29 Jul 2026)
• CVE-2026-64647 (5.4 Medium, published 27 Jul 2026)
• CVE-2026-52846 (4.2 Medium, published 24 Jul 2026)

CVE-2025-5271 on other distributions

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

Details

Affected Packages

References