CVE-2026-124853Improper Restriction of Operations within the Bounds of a Memory Buffer

NVDCVSS scored by 134c704f-9b21-4f2e-91b3-4a467353bcc0

Vulnerability Summary

Sandbox escape due to incorrect boundary conditions in the Graphics: Text component. This vulnerability was fixed in Firefox 160, Firefox ESR 115.45, Firefox ESR 153.7, Thunderbird 160, and Thunderbird 153.7.

Severity Level

CRITICAL(9.6)

Published Date

Nov 10, 2026

Last Modified

Nov 12, 2026

Exploitation Status

No confirmed exploitation yet

EPSS Score (30-Day)

0.41%Probability

Root Weakness (CWE)

CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer ↗

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the intended boundary of the buffer.

CVSS v3.1 Base Metrics — Score 9.6 (CRITICAL)

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

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeChanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

Affected & Patched Versions

Affected Versions

Not provided by NVD for this CVE.

Patched Versions

No patched version published yet

Until a fix ships, reduce exposure:

Restrict access to the affected service or interface to trusted networks.
Disable the affected feature if you do not need it.
Watch the vendor advisory for a firmware or software update.

What to do

Plan remediation soon. No exploitation is confirmed yet, but the severity is critical.

Check whether you run the affected product and which version.
No patched version is listed yet. Limit access to the affected service to trusted networks, and disable the feature if you can.
Subscribe to the vendor advisory so you learn when a fix ships.

Timeline

Nov 10, 2026Published
Nov 12, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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External References

Issue Trackinghttps://bugzilla.mozilla.org/show_bug.cgi?id=2058035
Vendor Advisoryhttps://www.mozilla.org/security/advisories/mfsa2026-125/
Vendor Advisoryhttps://www.mozilla.org/security/advisories/mfsa2026-126/
Vendor Advisoryhttps://www.mozilla.org/security/advisories/mfsa2026-127/
Vendor Advisoryhttps://www.mozilla.org/security/advisories/mfsa2026-128/
Vendor Advisoryhttps://www.mozilla.org/security/advisories/mfsa2026-129/

Data last checked: Nov 14, 2026 01:09 UTC