CVE-2026-12327: Vulnerability in Mozilla Firefox
Multiple memory safety vulnerabilities were identified in Mozilla Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151, and Thunderbird 151. These bugs showed evidence of memory corruption and could potentially be exploited to execute arbitrary code. The issues were addressed and fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird ESR 140.12. The vulnerabilities are classified as high severity with a CVSS score of 8.1.
AI Analysis
Technical Summary
CVE-2026-12327 describes memory safety bugs affecting Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151, and Thunderbird 151. Some of these bugs exhibited memory corruption, which could have allowed attackers to execute arbitrary code with sufficient effort. Mozilla released fixes for these vulnerabilities in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird ESR 140.12. The vulnerabilities are part of a broader set of memory safety issues addressed in these releases, with impacts ranging from moderate to high severity. The CVSS v3.1 base score is 8.1, indicating a high severity with network attack vector, high complexity, no privileges required, no user interaction, and high impact on confidentiality, integrity, and availability.
Potential Impact
The vulnerabilities could allow remote attackers to exploit memory corruption bugs to execute arbitrary code on affected systems. This could lead to full compromise of the affected Firefox or Thunderbird applications, impacting confidentiality, integrity, and availability. No known exploits in the wild have been reported at the time of disclosure.
Mitigation Recommendations
Official fixes are available and have been released by Mozilla. Users and administrators should update affected products to Firefox 152, Firefox ESR 140.12, Thunderbird 152, or Thunderbird ESR 140.12 to remediate these vulnerabilities. Patch status is confirmed by Mozilla advisories MFSA 2026-57 and MFSA 2026-58. No additional mitigation steps are required beyond applying these updates.
CVE-2026-12327: Vulnerability in Mozilla Firefox
Description
Multiple memory safety vulnerabilities were identified in Mozilla Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151, and Thunderbird 151. These bugs showed evidence of memory corruption and could potentially be exploited to execute arbitrary code. The issues were addressed and fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird ESR 140.12. The vulnerabilities are classified as high severity with a CVSS score of 8.1.
CVSS v3.1
Score 8.1high
Affected software
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-12327 describes memory safety bugs affecting Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151, and Thunderbird 151. Some of these bugs exhibited memory corruption, which could have allowed attackers to execute arbitrary code with sufficient effort. Mozilla released fixes for these vulnerabilities in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird ESR 140.12. The vulnerabilities are part of a broader set of memory safety issues addressed in these releases, with impacts ranging from moderate to high severity. The CVSS v3.1 base score is 8.1, indicating a high severity with network attack vector, high complexity, no privileges required, no user interaction, and high impact on confidentiality, integrity, and availability.
Potential Impact
The vulnerabilities could allow remote attackers to exploit memory corruption bugs to execute arbitrary code on affected systems. This could lead to full compromise of the affected Firefox or Thunderbird applications, impacting confidentiality, integrity, and availability. No known exploits in the wild have been reported at the time of disclosure.
Mitigation Recommendations
Official fixes are available and have been released by Mozilla. Users and administrators should update affected products to Firefox 152, Firefox ESR 140.12, Thunderbird 152, or Thunderbird ESR 140.12 to remediate these vulnerabilities. Patch status is confirmed by Mozilla advisories MFSA 2026-57 and MFSA 2026-58. No additional mitigation steps are required beyond applying these updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-06-15T15:08:22.115Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-57/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-58/","vendor":"Mozilla"}]
Threat ID: 6a314c830b89be6888b4cde7
Added to database: 06/16/2026, 13:15:47 UTC
Last enriched: 06/23/2026, 15:04:00 UTC
Last updated: 07/31/2026, 19:22:57 UTC
Views: 250
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.