Secuno
ENNL
Book demo

CVE-2025-11721

Mozilla Firefox buffer overflow

9.8 CRITICALEPSS 0.36%
  1. Published14 Oct 2025

Description

Memory safety bug present in Firefox 143 and Thunderbird 143. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 144 and Thunderbird 144.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Mozilla Firefox≥ 143.0 < 144.0
Mozilla Thunderbird≥ 143.0 < 144.0

Remediation

Fixed in
Mozilla Firefox≥ 144.0
Mozilla Thunderbird≥ 144.0

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

CVE-2026-10910910.0
A vulnerability was detected in Wavlink WL-WN530BE1-A 251117. This vulnerability…
CVE-2026-962658.2
IBM Power Systems Firmware FW1060.00 through FW1060.81 is affected by a vulnerability…
CVE-2026-1089159.9
A vulnerability has been found in Edimax BR-6208AC 1.32. This affects an unknown part…
CVE-2026-1089149.9
A flaw has been found in Edimax BR-6208AC 1.32. Affected by this issue is some unknown…
CVE-2026-1088939.9
A vulnerability was identified in Linksys E1700 up to 1.0.0.4.003. This issue affects…
CVE-2026-10889210.0
A vulnerability was determined in Linksys E1700 1.0.0.4.003. This vulnerability affects…

Frequently asked

Is CVE-2025-11721 being actively exploited?

CVE-2025-11721 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.36%.

How severe is CVE-2025-11721?

CVE-2025-11721 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.36% probability of exploitation.

Which products are affected by CVE-2025-11721?

Affected products include Mozilla Firefox, Mozilla Thunderbird.

How do I fix CVE-2025-11721?

Upgrade affected software to a fixed version, for example Mozilla Firefox 144.0, Mozilla Thunderbird 144.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-11721 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation worksBook a demo

Get Patch this first every Monday

Five vulnerabilities that matter this week, ranked on real exploitation. Plain language, one email, no spam.

You can unsubscribe with one click from every issue. We handle your details as described in our privacy policy.

Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.