🛡️ CVE-2023-5388 on Ubuntu — firefox

Distribution advisory

This page covers CVE-2023-5388 as tracked by Ubuntu, for the package firefox. The fix is available in version 124.0+build1-0ubuntu0.20.04.1; 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 none, availability low.

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:N/A:L

• 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: None.
• Availability impact: Low — limited, and the attacker does not choose what is affected.

Weakness class

UBUNTU-CVE-2023-5388 is classified as CWE-203: Observable Discrepancy. The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.

Affected software

UBUNTU-CVE-2023-5388 is recorded against 9 packages.

• firefox (fixed in 124.0+build1-0ubuntu0.20.04.1)
• mozjs102
• mozjs38
• mozjs52
• mozjs68
• mozjs78
• mozjs91
• nss (fixed in 2:3.98-0ubuntu0.22.04.1)
• thunderbird (fixed in 1:115.9.0+build1-0ubuntu0.22.04.1)

Timeline and source

Published on 23 October 2023 and last revised on 22 April 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
people.redhat.com (Report)
firefox-source-docs.mozilla.org (Report)
firefox-source-docs.mozilla.org (Report)
ubuntu.com (Advisory)
ubuntu.com (Advisory)
ubuntu.com (Advisory)
www.cve.org (Report)

Other advisories for this package

firefox has other advisories on record. If you are patching this one, these are worth checking on the same host:

• MGASA-2026-0325 (published 7 Aug 2026)
• CGA-9673-4hh7-5299 (published 30 Jul 2026)
• CGA-54vx-fp32-9r8x (published 30 Jul 2026)
• CGA-qc3v-v4g3-6j5f (published 30 Jul 2026)

Same weakness in other software

These advisories are the same class of weakness (CWE-203: Observable Discrepancy) in other software:

• CVE-2026-58445 (2.7 Low, published 13 Aug 2026)
• CVE-2025-13736 (3.7 Low, published 6 Aug 2026)
• CVE-2026-59640 (published 3 Aug 2026)
• CVE-2026-67193 (5.3 Medium, published 29 Jul 2026)
• CVE-2026-55555 (7.5 High, published 28 Jul 2026)
• CVE-2026-64713 (8.1 High, published 27 Jul 2026)
• CVE-2025-54999 (2.0 Low, published 27 Jul 2026)
• CVE-2026-44332 (5.3 Medium, published 24 Jul 2026)

CVE-2023-5388 on other distributions

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

Details

Affected Packages

References