PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-2759 Mozilla CVE debrief

CVE-2026-2759 is a critical vulnerability in the Mozilla Firefox browser, specifically affecting the Graphics: ImageLib component. The vulnerability was publicly disclosed on February 24, 2026, and has a CVSS score of 9.8, indicating a high severity level. The issue was addressed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8. Users are advised to update to the latest versions to mitigate potential risks. The vulnerability allows for arbitrary code execution, making it crucial for users to prioritize updates.

Vendor
Mozilla
Product
Firefox
CVSS
CRITICAL 9.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-02-24
Original CVE updated
2026-07-15
Advisory published
2026-02-24
Advisory updated
2026-07-15

Who should care

This vulnerability affects users of Mozilla Firefox, particularly those using versions prior to 148, Firefox ESR versions prior to 115.33 and 140.8, and Thunderbird versions prior to 148 and 140.8. Given the critical severity and potential for code execution, administrators and users of these affected products should prioritize patching to prevent exploitation.

Technical summary

The CVE-2026-2759 vulnerability is caused by incorrect boundary conditions in the Graphics: ImageLib component of Mozilla Firefox. This issue can lead to arbitrary code execution, making it a critical concern for users of affected versions. The vulnerability was addressed through updates in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8. The CVSS vector for this vulnerability is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, indicating a high level of severity across various metrics.

Defensive priority

Given the critical severity of CVE-2026-2759 and its potential for arbitrary code execution, immediate patching is advised for all affected products. Prioritize updates to Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8 to mitigate risks.

Recommended defensive actions

  • Update Firefox to version 148 or later.
  • Update Firefox ESR to version 115.33 or later.
  • Update Firefox ESR to version 140.8 or later.
  • Update Thunderbird to version 148 or later.
  • Update Thunderbird to version 140.8 or later.
  • Verify that all affected systems and user workstations have the latest security patches applied.

Evidence notes

The CVE-2026-2759 vulnerability was publicly disclosed on February 24, 2026, with a CVSS score of 9.8. The issue was addressed by Mozilla through updates in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8. Multiple references, including vendor advisories and issue tracking links, are available for further information.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-2759 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-2759

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-2759 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-2759

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.