# CVE-2024-3863: CVE-2024-3863

Status: published. Published: 2024-04-16. Updated: 2026-11-03.

The executable file warning was not presented when downloading .xrm-ms files.  
*Note: This issue only affected Windows operating systems. Other operating systems are unaffected.* This vulnerability affects Firefox < 125, Firefox ESR < 115.10, and Thunderbird < 115.10.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Mozilla / Firefox: < 125 (affected, custom). Source: CNA: mozilla
- Mozilla / Firefox ESR: < 115.10 (affected, custom). Source: CNA: mozilla
- Mozilla / Thunderbird: < 115.10 (affected, custom). Source: CNA: mozilla

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*",
            "versionEndExcluding": "115.10.0",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*",
            "versionEndExcluding": "125.0",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "115.10",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 9.8 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H; source: ADP: CISA-ADP

- CVSS 3.1: 9.8 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H; source: NVD: nvd@nist.gov

- CVSS 3.1: 9.8 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H; source: NVD: 134c704f-9b21-4f2e-91b3-4a467353bcc0

- CISA KEV: No listing in collected sources

- EPSS: 0.81% as of 2026-11-03; percentile 57.03%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-434

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://bugzilla.mozilla.org/show_bug.cgi?id=1885855 (CNA: mozilla)

- https://www.mozilla.org/security/advisories/mfsa2024-18/ (CNA: mozilla)

- https://www.mozilla.org/security/advisories/mfsa2024-19/ (CNA: mozilla)

- https://www.mozilla.org/security/advisories/mfsa2024-20/ (CNA: mozilla)

- https://bugzilla.mozilla.org/show_bug.cgi?id=1885855 (ADP: CVE; x_transferred)

- https://www.mozilla.org/security/advisories/mfsa2024-18/ (ADP: CVE; x_transferred)

- https://www.mozilla.org/security/advisories/mfsa2024-19/ (ADP: CVE; x_transferred)

- https://www.mozilla.org/security/advisories/mfsa2024-20/ (ADP: CVE; x_transferred)

- https://bugzilla.mozilla.org/show_bug.cgi?id=1885855 (security@mozilla.org; Issue Tracking)

- https://www.mozilla.org/security/advisories/mfsa2024-18/ (security@mozilla.org; Vendor Advisory)

- https://www.mozilla.org/security/advisories/mfsa2024-19/ (security@mozilla.org; Vendor Advisory)

- https://www.mozilla.org/security/advisories/mfsa2024-20/ (security@mozilla.org; Vendor Advisory)

- https://bugzilla.mozilla.org/show_bug.cgi?id=1885855 (af854a3a-2127-422b-91ae-364da2661108; Issue Tracking)

- https://www.mozilla.org/security/advisories/mfsa2024-18/ (af854a3a-2127-422b-91ae-364da2661108; Vendor Advisory)

- https://www.mozilla.org/security/advisories/mfsa2024-19/ (af854a3a-2127-422b-91ae-364da2661108; Vendor Advisory)

- https://www.mozilla.org/security/advisories/mfsa2024-20/ (af854a3a-2127-422b-91ae-364da2661108; Vendor Advisory)

## Provenance

- CNA: mozilla: https://www.cve.org/CVERecord?id=CVE-2024-3863; retrieved 2026-11-03; source updated 2026-11-03

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-3863; retrieved 2026-11-04; source updated 2026-11-03

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2024-3863; retrieved 2026-11-03; source updated Not reported

Revision: 623ec7afb5abc18df93ccc73a77d93bf738b653338e334a5b1176dcfda24fe37

Canonical: https://y2.dev/cve/CVE-2024-3863

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.