Cyber Resilience

CVE-2026-2759

Mozilla Firefox ≤ 115.33.0

Published
24 February 2026
Modified
15 July 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0040 33th percentile
Risk Priority 71 floored blend · peak EPSS

Summary

CVE-2026-2759 is a critical-severity Improper Handling of Physical or Environmental Conditions (CWE-1384) vulnerability in Mozilla Firefox. Its CVSS base score is 9.8 (Critical).

Operationally, ranked at the 33th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to CP-12 (Safe Mode) and PE-13 (Fire Protection) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-2759 involves incorrect boundary conditions in the Graphics: ImageLib component of Mozilla products. It affects Firefox versions prior to 148, Firefox ESR versions prior to 115.33 and 140.8, Thunderbird versions prior to 148, and Thunderbird versions prior to 140.8. The vulnerability is associated with CWE-1384 and has a CVSS v3.1 base score of 9.8.

Remote attackers require no privileges or user interaction to exploit this vulnerability over the network with low attack complexity. Successful exploitation can result in high impacts to confidentiality, integrity, and availability, potentially enabling arbitrary code execution within the affected browser or mail client context.

Mozilla addressed the issue in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8. Further details on the patches and remediation are provided in Mozilla Security Advisories MFSA2026-13, MFSA2026-14, MFSA2026-15, and MFSA2026-16, as well as Bugzilla entry 2010933.

EU & UK References

Vulnerability Data

Incorrect boundary conditions in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CWE(s)

Related Threats

CVEs Like This One

CVE-2026-2757Same product: Mozilla Firefox
CVE-2026-2760Same product: Mozilla Firefox
CVE-2025-1016Same product: Mozilla Firefox
CVE-2026-0880Same product: Mozilla Firefox
CVE-2026-2758Same product: Mozilla Firefox
CVE-2025-10534Same product: Mozilla Firefox
CVE-2024-6615Same product: Mozilla Firefox
CVE-2026-12304Same product: Mozilla Firefox
CVE-2026-16380Same product: Mozilla Firefox
CVE-2024-10467Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 115.33.0 · ≤ 148.0 · 128.0 — 140.8.0
mozilla
thunderbird
≤ 140.8.0 · ≤ 148.0

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

EMP protection directly addresses an artificially induced physical/environmental threat.

Safe-mode entry on detected adverse conditions reduces impact without eliminating the root handling weakness.

Fire detection and suppression directly stops fire (an environmental condition) from damaging the system.

Maintaining temperature and humidity levels prevents environmental conditions from affecting system operation.

Isolation valves and shutoffs stop water damage (environmental condition) from reaching the system.

Known-state failure on component or environmental faults limits blast radius.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.IR-02 full match
prevents

Explicit protection of assets from environmental threats is the core mitigation for improper handling of those conditions.

DE.CM-02 mostly match
prevents

Monitoring the physical environment directly surfaces the conditions the weakness fails to handle.

PR.IR-03 partial match
prevents

Resilience mechanisms help withstand adverse environmental situations but do not specifically address detection or handling of the conditions themselves.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

degrades

Directly requires protection against physical and environmental threats that the weakness describes.

prevents

Ensures supporting utilities (power, HVAC) are protected, mitigating environmental-condition failures.

finds

Physical security monitoring can detect environmental anomalies or tampering.

mitigates

Ensures information security is maintained during physical or environmental disruptions.

mitigates

ICT readiness for business continuity includes resilience to environmental conditions.

mitigates

Physical perimeters reduce exposure to external environmental threats.

References