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PatchSiren cyber security CVE debrief

CVE-2026-2807 Mozilla CVE debrief

CVE-2026-2807 is a critical vulnerability affecting Firefox 147 and Thunderbird 147, involving memory safety bugs that could lead to arbitrary code execution. The bugs showed evidence of memory corruption, and it is presumed that with enough effort, some of these could have been exploited. The vulnerability was fixed in Firefox 148 and Thunderbird 148. Users are advised to update to the latest versions to mitigate the risk. This vulnerability has a CVSS score of 9.8, indicating a high severity level.

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

Organizations and individuals using Firefox 147 or Thunderbird 147 should prioritize updating to the latest versions to mitigate the risk of arbitrary code execution. This vulnerability's high CVSS score of 9.8 emphasizes its critical nature. IT teams and cybersecurity professionals should ensure that all instances of affected software are updated promptly.

Technical summary

CVE-2026-2807 involves memory safety bugs in Firefox 147 and Thunderbird 147. These bugs could lead to memory corruption and potentially allow for arbitrary code execution. The vulnerability was addressed in Firefox 148 and Thunderbird 148. 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. The CWE associated with this vulnerability is CWE-787.

Defensive priority

High priority should be given to updating Firefox and Thunderbird to versions 148 or later. Organizations should ensure that their IT teams and cybersecurity professionals are aware of the vulnerability and take immediate action to mitigate the risk.

Recommended defensive actions

  • Update Firefox to version 148 or later.
  • Update Thunderbird to version 148 or later.
  • Ensure that all instances of affected software are updated promptly.
  • Review and implement compensating controls if immediate updates are not feasible.
  • Monitor for any suspicious activity related to this vulnerability.

Evidence notes

The CVE record and NVD detail provide comprehensive information about CVE-2026-2807. The vulnerability was published on February 24, 2026, and modified on June 30, 2026. The source item URL provides additional details about the vulnerability, including references to bug reports and vendor advisories.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-2807 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-2807

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

  • CVE-2026-2807 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-2807

    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.