CVE-2026-109780critical9.8

Mitigation bypass in the DOM: Core & HTML component

Impact

A mitigation bypass vulnerability in the DOM: Core & HTML component affects Firefox and Thunderbird, fixed in version 158. The weakness is a protection mechanism failure.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Affected packages

This source has no supported package-version data for matching. You can read the advisory here, but this record alone cannot power a dependency check.

Affected products

Vendor version evidence. Product records are separate from automatic dependency matching.

Mozilla · mozilla

Firefox

1 range

mozilla version evidence

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unaffected

158 → through *

rpm versions

Other versions: unknown

Mozilla · mozilla

Thunderbird

1 range

mozilla version evidence

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unaffected

158 → through *

rpm versions

Other versions: unknown

Original source description

Mitigation bypass in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.

Inside the record

Evidence available

Package identity · not supplied

Version evidence

Remediation guidance · not supplied

Weakness classification

Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-109780

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-693 ↗

CWE-693 Protection Mechanism Failure

CISA-ADP

Contributing organizations · 2

mozilla

Assigning organization

2026-10-13

CISA-ADP

Additional data publisher

2026-10-26

What changed

Follow changes

No substantive changes have been recorded here yet. History starts when cve.new observes a change after tracking is enabled; earlier edits are not reconstructed.

Large field values are marked as truncated previews. Original source snapshots remain retained.

References

3 sources

bugzilla.mozilla.org/show_bug.cgi

Source referencemozilla

www.mozilla.org/security/advisories/mfsa2026-106/

Security advisorymozilla

www.mozilla.org/security/advisories/mfsa2026-109/

Security advisorymozilla

Priority and evidence

Not in CISA KEVNo package fix recorded

KEV coverage does not rule out exploitation.

KEV checked 31/10/2026, 15:15:33 UTC

CISA-ADP · CVSS:3.1 · 9.8

Assessment vector

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

Reading the signals

Severity · CVSS: Technical impact and attack conditions. The headline is the highest imported catalog score; sources may disagree.
Observed exploitation · KEV: An absent or unavailable KEV listing does not establish that exploitation has not occurred.
Predicted exploitation · EPSS: No EPSS estimate available in this record.

CISA-ADP · SSVC

CISA Coordinator · 2026-10-26

Exploitation: none
Automatable: yes
Technical Impact: total

SSVC describes the publisher’s decision context. Your organization’s exposure and priorities may differ.

Record details

Published: 13/10/2026, 12:29:35 UTC
Modified: 26/10/2026, 19:41:10 UTC
Last imported by cve.new: 29/10/2026, 14:29:28 UTC
Aliases: None recorded

Source evidence

Request a correction or dispute

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Find the responsible CNA →Official dispute and escalation process ↗

CVE CVE-2026-109780

Enrichment coverage

NVDNot fully checked

GHSANot fully checked

EUVDNot fully checked

EPSSNot fully checked

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