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VulnerabilityPublished Updated

CVE-2026-100759: Mozilla Firefox · CWE-457

Affects Mozilla FirefoxSource CVE Database V5

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Not known to be exploited · CVSS 8.1 High.

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
0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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
  • <157
  • <115.42
  • <140.17
Fixed in
  • 153.4
  • 157
  • 115.42
  • 140.17

AI-suggested

A fix is available and has been released by Mozilla. Users and administrators should update to Firefox ESR 153.4 or later, Firefox 157 or later, Thunderbird 157 or later, or the corresponding fixed ESR versions listed in the advisory. Applying these official updates will remediate the vulnerability.

Description

CVE-2026-100759 is a high-severity vulnerability in Mozilla Firefox and Thunderbird involving uninitialized memory in the Storage: Quota Manager component. This flaw could allow an attacker to cause confidentiality and integrity impacts. The issue has been fixed in multiple versions of Firefox ESR and Thunderbird.

References

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