CVE-2026-109772critical9.1

Same-origin policy bypass in the DevTools component

Impact

A same-origin policy bypass vulnerability in the DevTools component of Firefox and Thunderbird was fixed in version 158. The weakness is an origin validation error. Local access may be required to exploit this vulnerability.

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

Same-origin policy bypass in the DevTools 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-2026-109772

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-346 ↗

CWE-346 Origin Validation Error

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 30/10/2026, 23:40:32 UTC

CISA-ADP · CVSS:3.1 · 9.1

Assessment vector

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

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, 12:29:33 UTC
Modified: 26/10/2026, 19:41:32 UTC
Last imported by cve.new: 29/10/2026, 14:27:19 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-2026-109772

Enrichment coverage

NVDNot fully checked

GHSANot fully checked

EUVDNot fully checked

EPSSNot fully checked

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