Cyber Posture

CVE-2026-6765

Medium

Published: 21 April 2026

Published
21 April 2026
Modified
22 April 2026
KEV Added
Patch
CVSS Score 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS Score 0.0004 13.1th percentile
Risk Priority 11 60% EPSS · 20% KEV · 20% CVSS

Description

Information disclosure in the Form Autofill component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

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.

addresses: CWE-359

Automated marking identifies private personal information in outputs, tangibly reducing the ability to exploit weaknesses that result in its unauthorized exposure.

addresses: CWE-359

Privacy-specific attributes and their controlled association directly reduce exposure of private personal information through missing or incorrect labeling.

addresses: CWE-359

Preventing nonpublic personal information from public posting reduces unauthorized exposure of private personal data.

addresses: CWE-359

The control detects and protects against mining of private personal information, reducing unauthorized exposure of PII.

addresses: CWE-359

Privacy literacy training directly targets preventing exposure of personal information through user mishandling.

addresses: CWE-359

Tracking locations of sensitive data and access users reduces risk of private personal information exposure.

addresses: CWE-359

PIA explicitly identifies PII collection/use/disclosure flows and drives mitigations that reduce the likelihood of unauthorized exposure of private personal information.

addresses: CWE-359

The control specifically requires architectures that minimize privacy risk when processing PII, directly addressing exposure of personal information.

Security SummaryAI

CVE-2026-6765 is an information disclosure vulnerability in the Form Autofill component of Mozilla products. It affects Firefox versions prior to 150, Firefox ESR versions prior to 140.10, Thunderbird versions prior to 150, and Thunderbird versions prior to 140.10. The issue, classified under CWE-359 (Exposure of Private Information to an Unauthorized Actor), carries a CVSS v3.1 base score of 5.3, reflecting medium severity with network accessibility, low attack complexity, no privileges or user interaction required, unchanged scope, and low confidentiality impact.

Unauthenticated remote attackers can exploit this vulnerability over the network without user interaction. Successful exploitation allows disclosure of sensitive information stored or handled by the Form Autofill feature, such as autofill data, though the impact is limited to low confidentiality without affecting integrity or availability.

Mozilla Security Advisories (MFSA 2026-30, 32, 33, and 34) and the associated Bugzilla entry detail the fix applied in the specified versions. Mitigation requires updating to Firefox 150, Firefox ESR 140.10, Thunderbird 150, or Thunderbird 140.10, as no additional workarounds are mentioned.

Details

CWE(s)

Affected Products

mozilla
firefox
≤ 140.10.0 · ≤ 150.0
mozilla
thunderbird
≤ 140.10.0

MITRE ATT&CK Enterprise TechniquesAI

T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
T1555.003 Credentials from Web Browsers Credential Access
Adversaries may acquire credentials from web browsers by reading files specific to the target browser.
Why these techniques?

CVE enables remote unauthenticated extraction of browser autofill data (potentially including credentials), directly facilitating local data access and credential harvesting from web browsers.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

References