CVE-2026-5731: Vulnerability in Mozilla Firefox
Multiple memory safety vulnerabilities were identified in Mozilla Firefox and Thunderbird versions prior to Firefox 149. 0. 2, Firefox ESR 115. 34. 1, and Firefox ESR 140. 9. 1. These bugs showed evidence of memory corruption and could potentially be exploited to execute arbitrary code. Mozilla has released official patches addressing these issues in Firefox 149. 0.
AI Analysis
Technical Summary
CVE-2026-5731 encompasses multiple memory safety bugs affecting Firefox ESR 115.34.0, Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1, and Thunderbird 149.0.1. These vulnerabilities involve memory corruption that could potentially be exploited to run arbitrary code. Mozilla has addressed these issues by releasing updates Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2, and Thunderbird 149.0.2. The vendor advisories confirm that these fixes are available and users should upgrade to these versions to remediate the vulnerabilities.
Potential Impact
The vulnerabilities could allow an attacker to exploit memory corruption bugs to execute arbitrary code on affected systems. This represents a high impact as arbitrary code execution can lead to full compromise of the affected application and potentially the underlying system. There are no known exploits in the wild at this time.
Mitigation Recommendations
Mozilla has released official fixes for these vulnerabilities in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2, and Thunderbird 149.0.2. Users and administrators should promptly update to these versions to mitigate the risk. No additional mitigation steps are indicated by the vendor advisory.
CVE-2026-5731: Vulnerability in Mozilla Firefox
Description
Multiple memory safety vulnerabilities were identified in Mozilla Firefox and Thunderbird versions prior to Firefox 149. 0. 2, Firefox ESR 115. 34. 1, and Firefox ESR 140. 9. 1. These bugs showed evidence of memory corruption and could potentially be exploited to execute arbitrary code. Mozilla has released official patches addressing these issues in Firefox 149. 0.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-5731 encompasses multiple memory safety bugs affecting Firefox ESR 115.34.0, Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1, and Thunderbird 149.0.1. These vulnerabilities involve memory corruption that could potentially be exploited to run arbitrary code. Mozilla has addressed these issues by releasing updates Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2, and Thunderbird 149.0.2. The vendor advisories confirm that these fixes are available and users should upgrade to these versions to remediate the vulnerabilities.
Potential Impact
The vulnerabilities could allow an attacker to exploit memory corruption bugs to execute arbitrary code on affected systems. This represents a high impact as arbitrary code execution can lead to full compromise of the affected application and potentially the underlying system. There are no known exploits in the wild at this time.
Mitigation Recommendations
Mozilla has released official fixes for these vulnerabilities in Firefox ESR 115.34.1, Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2, and Thunderbird 149.0.2. Users and administrators should promptly update to these versions to mitigate the risk. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-04-07T12:43:11.413Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-25/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-26/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-27/","vendor":"Mozilla"}]
Threat ID: 69d50016aaed68159a219cd3
Added to database: 4/7/2026, 1:01:10 PM
Last enriched: 4/7/2026, 1:16:58 PM
Last updated: 4/7/2026, 2:31:08 PM
Views: 2
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.