CVE-2026-74955: Vulnerability in Mozilla Firefox
CVE-2026-74955 is a privilege escalation vulnerability in the Request Handling component of Mozilla Firefox and Thunderbird. This vulnerability allows an attacker to gain elevated privileges. It was fixed in Firefox version 154 and Firefox ESR 153.1, as well as Thunderbird versions 154 and 153.1. The vulnerability has a high severity rating with a CVSS score of 8.8. There are no known exploits in the wild at the time of this advisory.
AI Analysis
Technical Summary
CVE-2026-74955 describes a privilege escalation vulnerability in the Request Handling component of Mozilla Firefox and Thunderbird. The flaw allows an attacker to escalate privileges, potentially impacting confidentiality, integrity, and availability. Mozilla fixed this issue in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1. The CVSS v3.1 base score is 8.8, indicating high severity with network attack vector, low attack complexity, no privileges required, user interaction required, and high impact on confidentiality, integrity, and availability.
Potential Impact
Successful exploitation of this vulnerability could allow an attacker to escalate privileges within the affected application, potentially leading to full compromise of the user's environment within the context of the browser or email client. The high CVSS score reflects significant impact on confidentiality, integrity, and availability.
Mitigation Recommendations
This vulnerability has been officially fixed by Mozilla. Users and administrators should update affected products to Firefox 154, Firefox ESR 153.1, Thunderbird 154, or Thunderbird 153.1 or later versions to remediate this issue. No additional mitigation actions are required once the update is applied.
CVE-2026-74955: Vulnerability in Mozilla Firefox
Description
CVE-2026-74955 is a privilege escalation vulnerability in the Request Handling component of Mozilla Firefox and Thunderbird. This vulnerability allows an attacker to gain elevated privileges. It was fixed in Firefox version 154 and Firefox ESR 153.1, as well as Thunderbird versions 154 and 153.1. The vulnerability has a high severity rating with a CVSS score of 8.8. There are no known exploits in the wild at the time of this advisory.
CVSS v3.1
Score 8.8high
Affected software
Mozilla
Firefox
Mozilla
Thunderbird
pkg:github/mozilla/firefox-esrRun 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-2026-74955 describes a privilege escalation vulnerability in the Request Handling component of Mozilla Firefox and Thunderbird. The flaw allows an attacker to escalate privileges, potentially impacting confidentiality, integrity, and availability. Mozilla fixed this issue in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1. The CVSS v3.1 base score is 8.8, indicating high severity with network attack vector, low attack complexity, no privileges required, user interaction required, and high impact on confidentiality, integrity, and availability.
Potential Impact
Successful exploitation of this vulnerability could allow an attacker to escalate privileges within the affected application, potentially leading to full compromise of the user's environment within the context of the browser or email client. The high CVSS score reflects significant impact on confidentiality, integrity, and availability.
Mitigation Recommendations
This vulnerability has been officially fixed by Mozilla. Users and administrators should update affected products to Firefox 154, Firefox ESR 153.1, Thunderbird 154, or Thunderbird 153.1 or later versions to remediate this issue. No additional mitigation actions are required once the update is applied.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-08-17T11:58:10.442Z
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-74/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-77/","vendor":"Mozilla"}]
Threat ID: 6a845507c6e8be03323673e5
Added to database: 08/18/2026, 12:50:15 UTC
Last enriched: 09/11/2026, 22:02:35 UTC
Last updated: 10/02/2026, 05:03:04 UTC
Views: 39
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