CVE-2025-6436

Publication date 24 June 2025

Last updated 16 July 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

8.1 · High

Score breakdown

Description

Memory safety bugs present in Firefox 139 and Thunderbird 139. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 140 and Thunderbird < 140.

Read the notes from the security team

Status

Package Ubuntu Release Status
firefox 25.04 plucky
Not affected
24.10 oracular
Not affected
24.04 LTS noble
Not affected
22.04 LTS jammy
Not affected
thunderbird 25.04 plucky
Not affected
24.10 oracular
Not affected
24.04 LTS noble
Not affected
22.04 LTS jammy
Not affected
mozjs38 25.04 plucky Not in release
24.10 oracular Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
18.04 LTS bionic
Needs evaluation
mozjs52 25.04 plucky Not in release
24.10 oracular Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
20.04 LTS focal Ignored
18.04 LTS bionic Ignored
mozjs68 25.04 plucky Not in release
24.10 oracular Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
20.04 LTS focal Ignored
mozjs78 25.04 plucky Not in release
24.10 oracular Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Ignored
mozjs91 25.04 plucky Not in release
24.10 oracular Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Ignored
mozjs102 25.04 plucky Not in release
24.10 oracular Not in release
24.04 LTS noble Ignored
22.04 LTS jammy Ignored
mozjs115 25.04 plucky Ignored
24.10 oracular Ignored
24.04 LTS noble Ignored
22.04 LTS jammy Not in release

Notes

mdeslaur

mozjs* contain a copy of the SpiderMonkey JavaScript engine. It is not feasible to backport security fixes to the mozjs* packages, as such, marking them as ignored. starting with Ubuntu 22.04, the firefox package is just a script that installs the Firefox snap starting with Ubuntu 24.04, the thunderbird package is just a script that installs the Thunderbird snap

Severity score breakdown

Parameter Value
Base score 8.1 · High
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Other references

Access our resources on patching vulnerabilities