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8.8
HIGH CVSS 3.1
CVE-2026-74949
Privilege escalation due to use-after-free in the Graphics: Canvas2D component
Overview
Description

Privilege escalation due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

Details
INFO

Published Date :

Aug. 18, 2026, 1:17 p.m.

Last Modified :

Sept. 1, 2026, 10:17 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Impact
Affected Products

The following products are affected by CVE-2026-74949 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Mozilla firefox
2 Mozilla thunderbird
: Total Affected Vendor : 1 | Products : 2
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 3.1 HIGH 134c704f-9b21-4f2e-91b3-4a467353bcc0
Solution
Update Firefox to a patched version to fix privilege escalation.
  • Update Firefox to version 154 or later.
  • Update Firefox ESR to version 140.14 or 153.1 or later.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-74949.

URL Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=2060245 Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-74/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-76/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-77/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-78/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-79/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-80/ Vendor Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-74949 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-74949 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-74949 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-74949 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    Sep. 01, 2026

    Action Type Old Value New Value
    Changed Description Use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1. Privilege escalation due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    Added Reference https://bugzilla.mozilla.org/show_bug.cgi?id=2060245
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-74/
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-76/
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-77/
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-78/
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-79/
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-80/
    Removed Reference https://bugzilla.mozilla.org/show_bug.cgi?id=2060245
    Removed Reference https://www.mozilla.org/security/advisories/mfsa2026-74/
    Removed Reference https://www.mozilla.org/security/advisories/mfsa2026-76/
    Removed Reference https://www.mozilla.org/security/advisories/mfsa2026-77/
    Removed Reference https://www.mozilla.org/security/advisories/mfsa2026-78/
    Removed Reference https://www.mozilla.org/security/advisories/mfsa2026-79/
    Removed Reference https://www.mozilla.org/security/advisories/mfsa2026-80/
    Removed Reference Type https://bugzilla.mozilla.org/show_bug.cgi?id=2060245 Types: Permissions Required
    Removed Reference Type https://www.mozilla.org/security/advisories/mfsa2026-74/ Types: Vendor Advisory
    Removed Reference Type https://www.mozilla.org/security/advisories/mfsa2026-76/ Types: Vendor Advisory
    Removed Reference Type https://www.mozilla.org/security/advisories/mfsa2026-77/ Types: Vendor Advisory
    Removed Reference Type https://www.mozilla.org/security/advisories/mfsa2026-78/ Types: Vendor Advisory
    Removed Reference Type https://www.mozilla.org/security/advisories/mfsa2026-79/ Types: Vendor Advisory
    Removed Reference Type https://www.mozilla.org/security/advisories/mfsa2026-80/ Types: Vendor Advisory
  • CVE Modified by [email protected]

    Aug. 24, 2026

    Action Type Old Value New Value
    Changed Description Privilege escalation due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1. Use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Aug. 21, 2026

    Action Type Old Value New Value
    Changed SSVC {'id': 'CVE-2026-74949', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-08-18T15:34:42.731131Z'} {'id': 'CVE-2026-74949', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-08-20T00:00:00+00:00'}
  • Initial Analysis by [email protected]

    Aug. 19, 2026

    Action Type Old Value New Value
    Added CPE Configuration OR *cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* versions from (including) 141.0 up to (excluding) 153.1.0 *cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* versions up to (excluding) 140.14.0 *cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* versions up to (excluding) 140.14.0 *cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* versions from (including) 141.0.0 up to (excluding) 153.1.0
    Added Reference Type Mozilla Corporation: https://bugzilla.mozilla.org/show_bug.cgi?id=2060245 Types: Permissions Required
    Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-74/ Types: Vendor Advisory
    Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-76/ Types: Vendor Advisory
    Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-77/ Types: Vendor Advisory
    Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-78/ Types: Vendor Advisory
    Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-79/ Types: Vendor Advisory
    Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-80/ Types: Vendor Advisory
  • CVE Modified by [email protected]

    Aug. 18, 2026

    Action Type Old Value New Value
    Changed Affected [{'vendor': 'Mozilla', 'product': 'Firefox', 'versions': [{'status': 'unaffected', 'version': '140.14', 'versionType': 'rpm', 'lessThanOrEqual': '140.*'}, {'status': 'unaffected', 'version': '153.1', 'versionType': 'rpm', 'lessThanOrEqual': '153.*'}, {'status': 'unaffected', 'version': '154', 'versionType': 'rpm', 'lessThanOrEqual': '*'}]}] [{'vendor': 'Mozilla', 'product': 'Firefox', 'versions': [{'status': 'unaffected', 'version': '140.14', 'versionType': 'rpm', 'lessThanOrEqual': '140.*'}, {'status': 'unaffected', 'version': '153.1', 'versionType': 'rpm', 'lessThanOrEqual': '153.*'}, {'status': 'unaffected', 'version': '154', 'versionType': 'rpm', 'lessThanOrEqual': '*'}]}, {'vendor': 'Mozilla', 'product': 'Thunderbird', 'versions': [{'status': 'unaffected', 'version': '140.14', 'versionType': 'rpm', 'lessThanOrEqual': '140.*'}, {'status': 'unaffected', 'version': '153.1', 'versionType': 'rpm', 'lessThanOrEqual': '153.*'}, {'status': 'unaffected', 'version': '154', 'versionType': 'rpm', 'lessThanOrEqual': '*'}]}]
    Changed Description Privilege escalation due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1. Privilege escalation due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-78/
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-79/
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-80/
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Aug. 18, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
    Added CWE CWE-416
    Added SSVC {'id': 'CVE-2026-74949', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-08-18T15:34:42.731131Z'}
  • New CVE Received by [email protected]

    Aug. 18, 2026

    Action Type Old Value New Value
    Added Affected [{'vendor': 'Mozilla', 'product': 'Firefox', 'versions': [{'status': 'unaffected', 'version': '140.14', 'versionType': 'rpm', 'lessThanOrEqual': '140.*'}, {'status': 'unaffected', 'version': '153.1', 'versionType': 'rpm', 'lessThanOrEqual': '153.*'}, {'status': 'unaffected', 'version': '154', 'versionType': 'rpm', 'lessThanOrEqual': '*'}]}]
    Added Description Privilege escalation due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, and Firefox ESR 153.1.
    Added Reference https://bugzilla.mozilla.org/show_bug.cgi?id=2060245
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-74/
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-76/
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-77/
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 8.8
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact