CVE-2026-6777
Published: 21 April 2026
Description
Other issue in the Networking: DNS component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.
Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.
Monitors for resource exhaustion and denial-of-service patterns that indicate uncontrolled consumption.
Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.
Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.
Awareness training educates users on avoiding untrusted links and actions that can be exploited via CSRF.
Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.
Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.
Security SummaryAI
CVE-2026-6777 is an unspecified vulnerability classified as "other issue" in the Networking: DNS component of Mozilla Firefox and Thunderbird. The flaw, associated with CWE-20 (Improper Input Validation), CWE-352 (Cross-Site Request Forgery), and CWE-400 (Uncontrolled Resource Consumption), carries a CVSS v3.1 base score of 5.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L), indicating medium severity with primary impact on availability.
Remote attackers can exploit this vulnerability over the network without authentication or user interaction, requiring low attack complexity. Successful exploitation results in a low-impact denial of service, such as resource exhaustion or service disruption, but does not compromise confidentiality or integrity.
Mozilla's security advisories (MFSA 2026-30 and MFSA 2026-33) and the associated Bugzilla entry (bug 2022726) confirm the issue was addressed in Firefox version 150 and Thunderbird version 150. Security practitioners should ensure affected users upgrade to these patched versions to mitigate the risk.
Details
- CWE(s)
Affected Products
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability in client DNS handling (improper input validation + resource consumption) enables remote exploitation to trigger application-level denial of service via resource exhaustion.