CVE-2026-8401

Description

Sandbox escape in the Profile Backup component. This vulnerability was fixed in Firefox 150.0.3.

Overview

State: PUBLISHED
Assigner (CNA): mozilla
CVSS severity: critical
CVSS score: 9.8 / 10
CVSS vector: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Effective score: 9.8 / 10 CRITICAL source: CNA overview
CWE(s): —
Reserved: 2026-05-12
Published: 2026-05-12 16:24 UTC
Last updated: 2026-05-14 21:54 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/8xxx/CVE-2026-8401.json
Linked Threat: CVE-2026-8401 — CVE-2026-8401

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-05-12 15:16:20 UTC
NVD last modified: 2026-05-19 18:16:31 UTC
NVD CVSS v3.1: 9.8 / 10 CRITICAL source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploitability subscore: 3.9 / 10
Impact subscore: 5.9 / 10
EPSS score: 0.0008 (probability of exploitation in next 30 days)
EPSS percentile: 24.27% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

NVD-assigned CWE(s): CWE-693 (differs from the CNA list above)

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-29493
Assigner: mozilla
Published: May 12, 2026, 2:24:33 PM
Updated: May 19, 2026, 5:10:47 PM
EUVD base score (CVSS 3.1): 9.8 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EUVD-reported EPSS: 0.0800
Vendors: Mozilla
Products: Firefox

ENISA description: Sandbox escape in the Profile Backup component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.

EUVD references (5)

Affected products (1)

Vendor	Product	Versions	Platforms
Mozilla	Firefox	`150.0.3` (unaffected)	—

Affected products — CPE 2.3 (1) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*

Vendor references (2)

References embedded in the original CVE record by the assigning CNA.

MITRE references (2) cveawg.mitre.org

Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.

Web references (13)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

http://www.mozilla.org/security/announce/2026/mfsa2026-51.html rapid7:www.mozilla.org
http://www.mozilla.org/security/announce/2026/mfsa2026-48.html rapid7:www.mozilla.org
http://www.mozilla.org/security/announce/2026/mfsa2026-47.html rapid7:www.mozilla.org
http://cwe.mitre.org/data/definitions/693.html rapid7:cwe.mitre.org
http://www.mozilla.org/security/announce/2026/mfsa2026-45.html rapid7:www.mozilla.org
https://attackerkb.com/topics/CVE-2026-8401 rapid7:attackerkb.com
https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-29493 rapid7:euvd.enisa.europa.eu
https://www.mozilla.org/security/advisories/mfsa2026-48/ tenable:www.mozilla.org
https://www.mozilla.org/security/advisories/mfsa2026-51/ tenable:www.mozilla.org
https://www.cve.org/CVERecord?id=CVE-2026-8401 tenable:www.cve.org
https://www.first.org/epss/ tenable:www.first.org
https://nvd.nist.gov/vuln/detail/CVE-2026-8401 tenable:nvd.nist.gov
https://www.mozilla.org/security/advisories/mfsa2026-47/ tenable:www.mozilla.org

NVD-tagged references (5)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://bugzilla.mozilla.org/show_bug.cgi?id=2038679 security@mozilla.org Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-45/ security@mozilla.org Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-47/ security@mozilla.org
https://www.mozilla.org/security/advisories/mfsa2026-48/ security@mozilla.org
https://www.mozilla.org/security/advisories/mfsa2026-51/ security@mozilla.org

Remediations (14)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CVE-2026-8401 - Vulnerability Details - OpenCVE

web:app.opencve.io

Remediation No vendor fix or workaround currently provided. OpenCVE Recommended Actions Install the vendor patch by updating to Firefox 150.0.3, ESR 115.36, or ESR 140.11, depending on the environment. If an upgrade cannot be applied immediately, disable the automatic profile backup feature or ensure that only trusted backup files are restored.

2026-05-23 20:58 UTC
Microsoft Patch Tuesday for May 2026 — Snort rules and prominent ...

web:blog.talosintelligence.com

Microsoft has released its monthly security update for May 2026 , which includes 137 vulnerabilities affecting a range of products, including 16 that Microsoft marked as "critical".

2026-05-23 20:58 UTC
CISA Warns of Exploited Microsoft Defender 0-Day Flaws

web:cyberpress.org

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .

2026-05-23 20:58 UTC
Microsoft Patch Tuesday March 2026 - 78 Vulnerabilities Fixed ...

web:cybersecuritynews.com

Microsoft released its March 2026 Patch Tuesday security update on March 10, 2026 , addressing 78 vulnerabilities across Windows, Microsoft Office, Azure, SQL Server, and .NET. The update includes one actively exploited zero-day vulnerability and multiple Critical-rated flaws demanding immediate attention from security teams. The most urgent fix this month is CVE - 2026 -21262, the sole zero-day ...

2026-05-23 20:58 UTC
Nvd - Cve-2026-8401

web:nvd.nist.gov

An official website of the United States government Here's how you know

2026-05-23 20:58 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

2026-05-23 20:58 UTC
2 New Microsoft Defender Zero-Days Exploited—Patch Now ... - Forbes

web:www.forbes.com

Microsoft has confirmed an emergency security update as CISA warns that two new Defender zero-days are being exploited by attackers.

2026-05-23 20:58 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-05-23 20:58 UTC
Windows 11 April 2026 Update tested: What's new, improved and fixed

web:www.windowslatest.com

Windows 11 April 2026 update adds Narrator Copilot support, faster Settings, File Explorer fixes, and key security improvements.

2026-05-23 20:58 UTC
Patch Tuesday May 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-05-23 20:58 UTC
Windows Kerberos RC4 deprecation: what will break in Active ... - 4sysops

web:4sysops.com

Starting in April 2026 , Windows updates will change the default Kerberos ticket issuance behavior to AES-SHA1 for accounts without explicit encryption settings, while RC4 can still be used where explicitly enabled. This change, driven by CVE - 2026 -20833, affects every Windows Server environment where service accounts or devices still rely on RC4. Any service account, NAS device, or legacy ...

2026-05-26 02:53 UTC
Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-05-26 02:53 UTC
February's Patch Tuesday release fixes 59 flaws ... - Computerworld

web:www.computerworld.com

Each month, the team at Readiness analyzes the latest Patch Tuesday updates from Microsoft and provides detailed, actionable testing guidance. The company's Patch Tuesday release for February ...

2026-05-26 02:53 UTC
Microsoft Confirms Active 0-Day Exploit—Check Emergency Mitigation

web:www.forbes.com

Updated May 17: This article, originally published May 16, has been updated to include further details on the emergency mitigation process recommended after the CVE - 2026 -42897 Microsoft Exchange ...

2026-05-26 02:53 UTC

AI Forensic Analysis

Only Available for Registered Users. Sign in to view.

Raw JSON

The full cvelistV5 record. Download as CVE-2026-8401.json.

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.8,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-8401",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-14T16:46:22.547730Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-693",
                "description": "CWE-693 Protection Mechanism Failure",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-14T19:54:10.869Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Firefox",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "150.0.3",
              "versionType": "rpm"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "ggwhyp"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Sandbox escape in the Profile Backup component. This vulnerability was fixed in Firefox 150.0.3."
            }
          ],
          "value": "Sandbox escape in the Profile Backup component. This vulnerability was fixed in Firefox 150.0.3."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-12T15:07:19.536Z",
        "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
        "shortName": "mozilla"
      },
      "references": [
        {
          "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2038679"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-45/"
        }
      ],
      "title": "Sandbox escape in the Profile Backup component"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
    "assignerShortName": "mozilla",
    "cveId": "CVE-2026-8401",
    "datePublished": "2026-05-12T14:24:33.320Z",
    "dateReserved": "2026-05-12T14:19:41.837Z",
    "dateUpdated": "2026-05-14T19:54:10.869Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}