CVE-2026-100766

4.3 MEDIUM 0.3% exploit odds Fix listed Disclosure Browser & mail

What it is

Information disclosure in the Networking: JAR component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

At a glance

Exploitability: Can be exploited over the network without logging in, but needs a user to act. Limited direct impact.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-09-29 13:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-13 18:00 UTC Last updatedMost recent change to the record

Details

Published: 2026-09-29 13:17 UTC
Last modified: 2026-10-13 18:00 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-200 · Information exposure
Record status: Analyzed

Affected

Mozilla Firefox < 115.42.0
Mozilla Firefox < 140.17.0
Mozilla Firefox < 153.4.0
Mozilla Firefox < 157.0.0
Mozilla Thunderbird < 140.17.0
Mozilla Thunderbird < 153.4.0
Mozilla Thunderbird < 157.0

Attack profile CVSS 3.1 · 4.3

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

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Fix and advisories

References

NVD record · CVE.org record