CVE-2026-7322
Published: 28 April 2026
Summary
CVE-2026-7322 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Mozilla Firefox. Its CVSS base score is 7.3 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 23.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-7322 encompasses multiple memory safety bugs, classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-416 (Use After Free), affecting Thunderbird ESR 140.10.0 and Thunderbird 150.0.0. These bugs demonstrate evidence of memory corruption, which Mozilla assesses as potentially exploitable for arbitrary code execution with sufficient effort. The vulnerability carries a CVSS v3.1 base score of 7.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L) and was published on 2026-04-28.
Remote attackers can exploit this vulnerability over the network with low complexity, without requiring user privileges or interaction. Successful exploitation could enable arbitrary code execution through memory corruption, resulting in low impacts to confidentiality, integrity, and availability within the affected Thunderbird processes.
Mozilla advisories MFSA2026-35 through MFSA2026-38 detail the fixes, available in Firefox 150.0.1, Firefox ESR 140.10.1, Firefox ESR 115.35.1, Thunderbird 150.0.1, and Thunderbird ESR 140.10.1. Additional technical details are provided in the associated Bugzilla entries. Security practitioners should prioritize updating affected Thunderbird installations to mitigate this issue.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-26059
Vulnerability details
Memory safety bugs present in Thunderbird ESR 140.10.0 and Thunderbird 150.0.0. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability…
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was fixed in Firefox 150.0.1, Firefox ESR 140.10.1, Firefox ESR 115.35.1, Thunderbird 150.0.1, and Thunderbird 140.10.1.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Memory corruption vulnerability (CWE-119, CWE-416) in Thunderbird client application enabling remote arbitrary code execution with no user interaction required.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mandates timely identification, reporting, and correction of software flaws like the memory safety bugs in Thunderbird, preventing exploitation through patching to fixed versions.
Implements memory protection mechanisms such as address space layout randomization and data execution prevention to block arbitrary code execution from memory corruption vulnerabilities like CWE-119 and CWE-416.
Requires vulnerability scanning to detect the presence of this specific CVE in Thunderbird installations, enabling proactive remediation.