CVE-2026-8973

Description

Memory safety bugs present in Thunderbird 150. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

Description (MITRE) cveawg.mitre.org

Pulled from cveawg.mitre.org/api/cve/CVE-2026-8973 on 2026-07-05. Shown when MITRE's text differs from the cvelistV5 mirror.

Memory safety bugs present in Firefox 150. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

Overview

State: PUBLISHED
Assigner (CNA): mozilla
CVSS severity: high
CVSS score: 8.8 / 10
CVSS vector: AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Effective score: 8.8 / 10 HIGH source: CNA overview
CWE(s): —
Reserved: 2026-05-19
Published: 2026-05-19 12:30 UTC
Last updated: 2026-05-20 15:39 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/8xxx/CVE-2026-8973.json
Linked Threat: CVE-2026-8973 — CVE-2026-8973

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: 2026-05-19 14:16:53 UTC
NVD last modified: 2026-05-20 17:50:51 UTC
NVD CVSS v3.1: 8.8 / 10 HIGH source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploitability subscore: 2.8 / 10
Impact subscore: 5.9 / 10
EPSS score: 0.0004 (probability of exploitation in next 30 days)
EPSS percentile: 11.85% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

NVD-assigned CWE(s): CWE-119 (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-2026-30923
Assigner: mozilla
Published: May 19, 2026, 12:30:21 PM
Updated: May 26, 2026, 5:47:40 PM
EUVD base score (CVSS 3.1): 8.8 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EUVD-reported EPSS: 0.0400
Aliases: GHSA-f4hm-8h94-gvp6

ENISA description: Memory safety bugs present in Firefox 150. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

EUVD references (3)

Affected products (2)

Vendor	Product	Versions	Platforms
Mozilla	Firefox	`151` (unaffected)	—
Mozilla	Thunderbird	`151` (unaffected)	—

Affected products — CPE 2.3 (2) 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:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*

Vendor references (3)

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

Web references (11)

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/mfsa2026-50.html rapid7:www.mozilla.org
http://www.mozilla.org/security/announce/2026/mfsa2026-46.html rapid7:www.mozilla.org
https://attackerkb.com/topics/CVE-2026-8973 rapid7:attackerkb.com
http://cwe.mitre.org/data/definitions/119.html rapid7:cwe.mitre.org
https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-30923 rapid7:euvd.enisa.europa.eu
https://www.mozilla.org/security/advisories/mfsa2026-50/ tenable:www.mozilla.org
https://nvd.nist.gov/vuln/detail/CVE-2026-8973 tenable:nvd.nist.gov
https://www.cve.org/CVERecord?id=CVE-2026-8973 tenable:www.cve.org
https://www.first.org/epss/ tenable:www.first.org
https://www.mozilla.org/security/advisories/mfsa2026-46/ tenable:www.mozilla.org
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1362365%2C1860538%2C1929005%2C1983353%2C1998526%2C2023271%2C2023943%2C2024244%2C2024260%2C2024443%2C2024665%2C2024774%2C2024916%2C2025346%2C2025357%2C2025406%2C2025434%2C2025488%2C2025496%2C2025942%2C2025947%2C2025968%2C2026279%2C2027159%2C2027239%2C2027276%2C2027308%2C2027310%2C2027324%2C2027329%2C2027363%2C2027381%2C2027382%2C2027383%2C2028274%2C2028884%2C2029060%2C2029065%2C2029068%2C2029281%2C2029293%2C2029297%2C2029303%2C2029439%2C2029448%2C20 tenable:bugzilla.mozilla.org

NVD-tagged references (3)

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

Remediations (15)

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

CVE-2026-8973 | CVE Alert & Security Feed

web:cvealert.net

CVE-2026-8973 - UNKNOWN vulnerability with CVSS score 0.0

2026-05-23 22:18 UTC
CVE-2026-8973 - Memory safety bugs fixed in Thunderbird 151

web:cvefeed.io

Memory safety bugs present in Thunderbird 150. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

2026-05-23 22:18 UTC
CVE-2026-8973 - CRITICAL Severity Vulnerability | CVEInfo.com

web:cveinfo.com

Memory safety bugs present in Thunderbird 150. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these...

2026-05-23 22:18 UTC
CVE-2026-8973 - Exploits & Severity - Feedly

web:feedly.com

[High] Memory safety bugs present in Firefox 150. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

2026-05-23 22:18 UTC
Nvd - Cve-2026-8973

web:nvd.nist.gov

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

2026-05-23 22:18 UTC
CVE-2026-8973 - security-tracker.debian.org

web:security-tracker.debian.org

Vulnerable and fixed packages The table below lists information on source packages.

2026-05-23 22:18 UTC
CVE-2026-8973 : Memory Safety Bugs in Firefox from Mozilla

web:securityvulnerability.io

Memory safety flaws in Firefox can lead to potential code execution. Learn about this vulnerability and its impact with CVE-2026-8973 .

2026-05-23 22:18 UTC
Addressing Exchange Server May 2026 vulnerability CVE-2026-42897

web:techcommunity.microsoft.com

We wanted to tell you how to address the Exchange Server May 2026 vulnerability CVE - 2026 -42897.

2026-05-23 22:18 UTC
CVE-2026-8973 - Memory safety bugs fixed in Thunderbird 151

web:www.nmmapper.com

cve details for CVE-2026-8973 - Memory safety bugs fixed in Thunderbird 151 viewing details and related vulnerabilities.

2026-05-23 22:18 UTC
CVE-2026-8973 - High Vulnerability - TheHackerWire

web:www.thehackerwire.com

To protect against CVE-2026-8973 , you should: (1) Apply the latest security patches from Mozilla, (2) Check official security advisories for specific remediation steps, (3) Update affected software to the latest version, and (4) Monitor your systems for any signs of exploitation.

2026-05-23 22:18 UTC
CVE-2026-8973 - Vulnerability Details - OpenCVE

web:app.opencve.io

Remediation No vendor fix or workaround currently provided. OpenCVE Recommended Actions Upgrade to Mozilla Thunderbird 151 or newer, and Firefox 151 or newer, to resolve the memory safety bugs.

2026-05-26 02:58 UTC
cveawg.mitre.org

web:cveawg.mitre.org

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2026-05-26 02:58 UTC
Memory safety bugs present in Firefox 150. Some of these...

web:github.com

GitHub is where people build software. More than 150 million people use GitHub to discover, fork, and contribute to over 420 million projects.

2026-05-26 02:58 UTC
CVE-2026-8973 | Ubuntu

web:ubuntu.com

Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things.

2026-05-26 02:58 UTC
CVE-2026-8973 | Tenable®

web:www.tenable.com

Memory safety bugs present in Thunderbird 150. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

2026-05-26 02:58 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-8973.json.

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