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CVE-2026-7323 Mozilla CVE debrief

CVE-2026-7323 is a high-severity vulnerability in Thunderbird ESR 140.10.0 and Thunderbird 150.0.0, 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 to run arbitrary code. This vulnerability was fixed in Firefox 150.0.1, Firefox ESR 140.10.1, Thunderbird 150.0.1, and Thunderbird 140.10.1. The CVSS score for this vulnerability is 7.3, indicating a high level of severity. The vulnerability was published on April 28, 2026, and modified on June 30, 2026.

Vendor
Mozilla
Product
Firefox
CVSS
HIGH 7.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-28
Original CVE updated
2026-07-15
Advisory published
2026-04-28
Advisory updated
2026-07-15

Who should care

Organizations and individuals using Thunderbird ESR 140.10.0, Thunderbird 150.0.0, Firefox 150.0.0, and Firefox ESR 140.10.0 should prioritize patching this vulnerability. Additionally, security teams and IT administrators responsible for maintaining and securing email clients and web browsers should be aware of this vulnerability and take necessary actions to mitigate potential risks.

Technical summary

CVE-2026-7323 is a high-severity vulnerability affecting Thunderbird ESR 140.10.0 and Thunderbird 150.0.0. The vulnerability involves 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 to run arbitrary code. The vulnerability was fixed in Firefox 150.0.1, Firefox ESR 140.10.1, Thunderbird 150.0.1, and Thunderbird 140.10.1. The CVSS vector for this vulnerability is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.

Defensive priority

Patching this vulnerability is of high priority due to its high CVSS score and potential impact on affected systems. Security teams should prioritize patching Thunderbird ESR 140.10.0, Thunderbird 150.0.0, Firefox 150.0.0, and Firefox ESR 140.10.0.

Recommended defensive actions

  • Patch Thunderbird ESR 140.10.0 and Thunderbird 150.0.0 to versions 140.10.1 and 150.0.1 respectively.
  • Patch Firefox 150.0.0 and Firefox ESR 140.10.0 to versions 150.0.1 and 140.10.1 respectively.
  • Review and update vulnerability management processes to ensure timely patching of high-severity vulnerabilities.
  • Monitor systems for potential exploitation attempts.
  • Conduct regular security audits to identify and address potential vulnerabilities.

Evidence notes

The CVE record and NVD detail provide information on the vulnerability, its impact, and the affected products. The Mozilla security advisories provide guidance on patching and mitigation. Red Hat errata provide additional information on the vulnerability and its impact on Red Hat products.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-7323 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-7323

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

  • CVE-2026-7323 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-7323

    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.