Security readout for executives and security teams
Plain-English summary
Firefox and Thunderbird could place credentials embedded in a URL into Content Security Policy reports instead of removing them. Anyone able to receive or access those reports might obtain the exposed HTTP Basic Authentication credentials. The supplied evidence does not indicate broader password theft.
Executive priority
Treat this as an urgent patching and credential-review issue, particularly where Basic Authentication or CSP reporting is used. Prioritize exposed endpoints and shared reporting systems. Escalate immediately to credential rotation if embedded credentials are found in reports or logs.
Technical view
Affected builds failed to strip URL userinfo—the username:password component—before serializing URLs into CSP reports. Mozilla fixed the issue in Firefox 141, ESR 128.13 and 140.1, and corresponding Thunderbird releases. The source establishes credential disclosure; it does not explain the CVSS vector’s claimed integrity and availability impacts.
Likely exposure
Exposure is most likely on corresponding branches below the fixed releases where credential-bearing URLs and CSP reporting are both used. Risk increases when reports are transmitted to third parties, centrally stored, broadly accessible, or retained in logs. Environment-specific prevalence is unknown.
Exploitation context
The supplied bundle reports no CISA KEV listing and provides no evidence of active exploitation. Abuse would depend on a CSP report containing a URL with embedded Basic Authentication credentials and an unauthorized party gaining access to that report or its storage.
Researcher notes
The vulnerability concerns incorrect sanitization of CSP report URLs. Fixed-version evidence is clear, but the bundle does not identify vulnerable starting versions, exploitation in the wild, required CSP directives, or precise report-access conditions. Validate those details against Mozilla guidance before defining exact detection coverage.
Mitigation direction
- Upgrade Firefox to 141, ESR 128.13 or ESR 140.1, as appropriate.
- Upgrade Thunderbird to 141, 128.13 or 140.1, as appropriate.
- Remove credentials from URLs and adopt safer authentication handling where feasible.
- Restrict access to CSP report endpoints, stored reports, and related logs.
- Rotate credentials if review identifies possible disclosure through CSP reports.
Validation and detection
- Inventory Firefox and Thunderbird versions across endpoints and managed images.
- Confirm each installation meets the fixed version for its release branch.
- Identify CSP report endpoints, processors, storage locations, recipients, and retention periods.
- Review reports safely for URL userinfo patterns without copying credential values.
- Verify potentially exposed credentials were rotated and report access is appropriately restricted.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-276: Exact CWE lookup
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Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2025-8031 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.mozilla.org/show_bug.cgi?id=1971719CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-56/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-58/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-59/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-61/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-62/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-63/CVE reference, mozilla
- https://lists.debian.org/debian-lts-announce/2025/07/msg00016.htmlCVE reference, CVE
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Incorrect Default Permissions
Incorrect Default Permissions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.