CVE-2025-49709

| EUVD-2025-18101 CRITICAL
2025-06-11 [email protected]
9.8
CVSS 3.1
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CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

4
Patch Released
Mar 31, 2026 - 21:13 nvd
Patch available
Analysis Generated
Mar 14, 2026 - 21:09 vuln.today
EUVD ID Assigned
Mar 14, 2026 - 21:09 euvd
EUVD-2025-18101
CVE Published
Jun 11, 2025 - 12:15 nvd
CRITICAL 9.8

Description

Certain canvas operations could have lead to memory corruption. This vulnerability affects Firefox < 139.0.4.

Analysis

Critical memory corruption vulnerability in Firefox canvas operations that allows unauthenticated remote attackers to achieve arbitrary code execution with no user interaction required. Firefox versions prior to 139.0.4 are affected. The vulnerability has a near-perfect CVSS score of 9.8 due to network accessibility, low attack complexity, and complete compromise of confidentiality, integrity, and availability.

Technical Context

This vulnerability exists in Firefox's canvas rendering implementation, specifically within canvas operation handlers that perform memory operations without proper bounds checking. The root cause is CWE-787 (Out-of-bounds Write), a buffer overflow condition where canvas operations write data beyond allocated memory boundaries. Canvas is a core HTML5 feature used for 2D graphics rendering in web browsers. The memory corruption occurs during specific canvas operations that are accessible to any web content loaded in the browser. The vulnerability affects the Gecko rendering engine used by Firefox, impacting all Firefox versions below 139.0.4 across Windows, macOS, and Linux platforms.

Affected Products

Firefox (< 139.0.4)

Remediation

Immediate action required: Update Firefox to version 139.0.4 or later. Mozilla's official security advisory should be consulted at https://www.mozilla.org/en-US/security/advisories/ for detailed patch information and release notes. Users on Windows, macOS, and Linux should enable automatic updates or manually download the latest Firefox release immediately. Organizations managing Firefox deployments should prioritize this update in their patch management systems. No known workarounds exist for this memory corruption vulnerability; patching is the only secure remediation. Disable Firefox or restrict web browsing until the patch can be applied if delay is anticipated.

Priority Score

49
Low Medium High Critical
KEV: 0
EPSS: +0.1
CVSS: +49
POC: 0

Vendor Status

Ubuntu

Priority: Medium
firefox
Release Status Version
jammy not-affected code not present
noble not-affected code not present
oracular not-affected code not present
plucky not-affected code not present
upstream needs-triage -
focal DNE -
questing not-affected code not present
thunderbird
Release Status Version
noble not-affected code not present
oracular not-affected code not present
plucky not-affected code not present
upstream needs-triage -
jammy not-affected code not present
focal DNE -
questing not-affected code not present
mozjs38
Release Status Version
bionic needs-triage -
jammy DNE -
noble DNE -
oracular DNE -
plucky DNE -
upstream needs-triage -
questing DNE -
mozjs52
Release Status Version
bionic ignored -
focal ignored -
jammy DNE -
noble DNE -
oracular DNE -
plucky DNE -
upstream needs-triage -
questing DNE -
mozjs68
Release Status Version
focal ignored -
jammy DNE -
noble DNE -
oracular DNE -
plucky DNE -
upstream needs-triage -
questing DNE -
mozjs78
Release Status Version
jammy ignored -
noble DNE -
oracular DNE -
plucky DNE -
upstream needs-triage -
questing DNE -
mozjs91
Release Status Version
jammy ignored -
noble DNE -
oracular DNE -
plucky DNE -
upstream needs-triage -
questing DNE -
mozjs102
Release Status Version
jammy ignored -
noble ignored -
oracular DNE -
plucky DNE -
upstream needs-triage -
questing DNE -
mozjs115
Release Status Version
jammy DNE -
noble ignored -
oracular ignored -
plucky ignored -
upstream needs-triage -
questing DNE -

Debian

firefox
Release Status Fixed Version Urgency
sid fixed 148.0.2-1 -
(unstable) fixed 139.0.4-1 -

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CVE-2025-49709 vulnerability details – vuln.today

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