All vulnerabilities
CVE-2026-100771

Firefox: Undefined behavior in the DOM: Streams component

Mozilla FirefoxApplications & CMS
Open in ThreatlineRecord JSON
CVSS
8.1High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.31%Chance of exploitation activity in the next 30 days, higher than 22% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published29 Sep 2026Updated 1 Oct 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

Description

Undefined behavior in the DOM: Streams 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.

Text from CVE List

Affected versions 7

  • Firefoxunaffected: 115.42 through 115.*CVE List
  • Firefoxunaffected: 140.17 through 140.*CVE List
  • Firefoxunaffected: 153.4 through 153.*CVE List
  • Firefoxunaffected: 157CVE List
  • Thunderbirdunaffected: 140.17 through 140.*CVE List
  • Thunderbirdunaffected: 153.4 through 153.*CVE List
  • Thunderbirdunaffected: 157CVE List

References 8