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VulnerabilityPublished Updated

CVE-2026-100798: Mozilla Firefox · CWE-325

Affects Mozilla FirefoxSource CVE Database V5

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Not known to be exploited · CVSS 8.1 High · fixed in 153.4 : patch Mozilla Firefox soon.

Data as of 12 Nov 2026, 23:24 UTC

CVSS 3.1 base score
8.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 153.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 29 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Mozilla FirefoxAffected
  • <153.4
Fixed in
  • 153.4

AI-suggested

A fix is available and has been released by Mozilla. Users and administrators should update affected products to Firefox ESR 153.4, Firefox 157, Thunderbird 157, or Thunderbird 153.4 or later versions to remediate this vulnerability. Refer to the Mozilla security advisories MFSA2026-100 and MFSA2026-97 for official patch details and update instructions.

Description

CVE-2026-100798 is a cryptography misuse vulnerability in the Storage: Quota Manager component of Mozilla Firefox. It affects Firefox versions prior to 153.4 and was fixed in Firefox ESR 153.4 and Firefox 157. The vulnerability has a high severity rating with a CVSS score of 8.1. No known exploits are reported in the wild. The issue also affects Thunderbird versions prior to 157 and 153.4, which were similarly fixed. This vulnerability could allow an attacker to compromise confidentiality and integrity without requiring privileges or authentication, but user interaction is required.

References

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