🛡️ CVE-2026-16381 — firefox

🔴 CVSS 9.1 — Critical ✅ No Known Exploit CWE-346 NVD
9.1
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Same-origin policy bypass in the Networking: DNS component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

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 high, integrity high, availability none.

Weakness class

CVE-2026-16381 is classified as CWE-346: Origin Validation Error. The origin of a message or request is not verified properly, so one source can pose as another.

Affected software

CVE-2026-16381 is recorded against 2 packages.

  • firefox (fixed in 153.0.0)
  • thunderbird (from 141.0 up to 153.0)

Timeline and source

Published on 21 July 2026 and last revised on 24 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

bugzilla.mozilla.org
www.mozilla.org
www.mozilla.org
www.mozilla.org
www.mozilla.org

Details

Severity CRITICAL
CVSS Score 9.1
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE CWE-346
Public Exploit ✅ No
Source NVD
Published 2026-07-21
Updated 2026-08-11
Modified 2026-07-24
Fix URL N/A

Affected Packages

Software From version Fixed in
firefox — 153.0.0
thunderbird 141.0 153.0

Similar Threats

Exploit Protection

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CVE-2026-16381 carries CVSS 9.1 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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