CVE-2025-8031
Mozilla Firefox ≤ 128.13.0
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2025-8031 is a critical-severity Incorrect Default Permissions (CWE-276) vulnerability in Mozilla Firefox. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Services File Permissions Weakness (T1574.010); ranked at the 36th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2025-8031 is a vulnerability in Mozilla Firefox and Thunderbird where the `username:password` component of URLs was not properly stripped from Content Security Policy (CSP) reports, potentially exposing HTTP Basic Authentication credentials. This issue, classified under CWE-276 (Incorrect Default Permissions), affects versions of Firefox prior to 141, Firefox ESR prior to 128.13 and 140.1, Thunderbird prior to 141, and Thunderbird ESR prior to 128.13 and 140.1. The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity due to its high impact on confidentiality, integrity, and availability.
A remote attacker can exploit this vulnerability over the network with low complexity, requiring no privileges or user interaction. By triggering a CSP violation on a page protected by HTTP Basic Authentication, the attacker can cause the browser to send a CSP report containing the unredacted URL with embedded credentials to a report endpoint under the attacker's control, leading to credential leakage. This enables unauthorized access to protected resources, potentially resulting in high-impact compromises.
Mozilla's security advisories (MFSA 2025-56, 58, 59, and 61) and the associated Bugzilla entry detail the fix implemented in the listed versions, recommending immediate updates to Firefox 141, Firefox ESR 128.13 or 140.1, Thunderbird 141, or Thunderbird ESR 128.13 or 140.1 as the primary mitigation. No workarounds are specified beyond applying the patches.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-22366
Vulnerability Data
The `username:password` part was not correctly stripped from URLs in CSP reports potentially leaking HTTP Basic Authentication credentials. This vulnerability was fixed in Firefox 141, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 11 hardening rules · 3 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Enforces approved authorizations on files and resources so overly permissive defaults cannot be exploited.
Requires least-privilege defaults so that installed files are not world-writable by default.
Requires documented, restrictive configuration settings that cover file and directory permissions.
Enforces access restrictions on changes, including permission settings applied during installation or configuration.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Hardened baselines and configuration management explicitly require correct default file permissions.
Defining and enforcing least-privilege access permissions directly prevents overly permissive defaults at install time.
Lifecycle management can encompass permission settings, yet the control is too broad to specifically mitigate incorrect defaults.
Secure SDLC practices include establishing secure defaults, but address only the development-phase portion of the weakness.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Standard templates that restrict access to utility programs and host parameter settings prevent the assignment of overly permissive default permissions on critical resources.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Windows Server 2016 (2 rules)
- V-224833 Permissions for program file directories must conform to minimum requirements. prevents CWE-276
- V-224834 Permissions for the Windows installation directory must conform to minimum requirements. prevents CWE-276
Windows Server 2019 (2 rules)
- V-205735 Windows Server 2019 permissions for program file directories must conform to minimum requirements. prevents CWE-276
- V-205736 Windows Server 2019 permissions for the Windows installation directory must conform to minimum requirements. prevents CWE-276
Windows Server 2022 (2 rules)
- V-254252 Windows Server 2022 permissions for program file directories must conform to minimum requirements. prevents CWE-276
- V-254253 Windows Server 2022 permissions for the Windows installation directory must conform to minimum requirements. prevents CWE-276