CVE-2026-2789
Published: 24 February 2026
Description
Use-after-free 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.
Mitigating Controls (NIST 800-53 r5)AI
Directly mandates timely remediation of the use-after-free flaw in Firefox/Thunderbird ImageLib by applying patches to fixed versions like Firefox 148.
Requires vulnerability scanning to identify systems running vulnerable versions of Firefox or Thunderbird affected by CVE-2026-2789.
Implements memory protections like ASLR and DEP to mitigate exploitation of the use-after-free vulnerability leading to arbitrary code execution.
Security SummaryAI
CVE-2026-2789 is a use-after-free vulnerability (CWE-416) in the Graphics: ImageLib component of Mozilla Firefox and Thunderbird. It affects versions of Firefox prior to 148, Firefox ESR prior to 115.33 and 140.8, Thunderbird prior to 148, and Thunderbird prior to 140.8. The issue has a CVSS v3.1 base score of 9.8, indicating critical severity due to its potential for high impact on confidentiality, integrity, and availability.
Remote attackers can exploit this vulnerability over the network with low complexity, requiring no privileges, no user interaction, and no change in scope. Successful exploitation could allow arbitrary code execution, potentially leading to full compromise of the affected browser or mail client, including theft of sensitive data, modification of system resources, or denial of service.
Mozilla's security advisories (MFSA 2026-13 through 2026-16) and the associated Bugzilla entry detail the patch releases that resolve the vulnerability. Security practitioners should ensure affected products are updated to Firefox 148, Firefox ESR 115.33 or 140.8, Thunderbird 148, or Thunderbird 140.8, as these versions include the necessary fixes to prevent exploitation.
Details
- CWE(s)
Affected Products
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Use-after-free in client-side ImageLib component enables remote arbitrary code execution in browser/email client apps (no privileges or interaction required), directly corresponding to Exploitation for Client Execution.