CyberSecBulletin
CVE-2026-2759NVD status: Modified

Firefox: Improper Handling of Physical or Environmental Conditions

Published Updated By the CyberSecBulletin desk

CVE-2026-2759 is a critical-severity improper handling of physical or environmental conditions vulnerability in Firefox from Mozilla, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.47% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of Firefox you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on mozilla.org for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
MozillaFirefoxNot specified in the recordNot stated
MozillaThunderbirdNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 10Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 10.0 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.2 Advanced Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-OnNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.6 Telecommunications Update ServiceNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.6 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update ServiceNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.0 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP SolutionsNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.4 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 9.6 Extended Update SupportNot specified in the recordNot stated
Red HatRed Hat Enterprise Linux 6Not specified in the recordNot stated
Red HatRed Hat Enterprise Linux 7Not specified in the recordNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalNVD
CVSS 3.19.8CriticalCISA (ADP)
CVSS 3.17.5HighCNA

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Handling of Physical or Environmental Conditions

The product does not properly handle unexpected physical or environmental conditions that occur naturally or are artificially induced.

How developers prevent this class of flaw

  • In requirements, be specific about expectations for how the product will perform when it exceeds physical and environmental boundary conditions, e.g., by shutting down.
  • Where possible, include independent components that can detect excess environmental conditions and have the capability to shut down the product.
  • Where possible, use shielding or other materials that can increase the adversary's workload and reduce the likelihood of being able to successfully trigger a security-related failure.

More Improper Handling of Physical or Environmental Conditions vulnerabilities (CWE-1384)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Firefox

All Firefox vulnerabilities

Recent Improper Handling of Physical or Environmental Conditions vulnerabilities

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