CVE-2025-6436
published 2025-06-24CVE-2025-6436: 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…
PriorityP348high8.1CVSS 3.1
AVNACHPRNUINSUCHIHAH
EPSS
2.92%
85.5th percentile
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 was fixed in Firefox 140 and Thunderbird 140.
Affected
5 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | firefox | < firefox 140.0-1 (sid) | firefox 140.0-1 (sid) |
| mozilla | firefox | < 140.0 | 140.0 |
| mozilla | firefox | — | — |
| mozilla | thunderbird | < 140.0 | 140.0 |
| mozilla | thunderbird | >= 0 < 1:140.7.1+build1-0ubuntu0.22.04.1 | 1:140.7.1+build1-0ubuntu0.22.04.1 |
CVSS provenance
nvdv3.18.1HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
osv8.1HIGH
vendor_debian8.1HIGH
vendor_redhat8.1HIGH
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Ubuntu
Thunderbird vulnerabilities
vendor_ubuntu·2026-02-02
CVE-2025-8031 Thunderbird vulnerabilities
Title: Thunderbird vulnerabilities
Summary: Several security issues were fixed in Thunderbird.
Multiple security issues were discovered in Thunderbird. If a user were
tricked into opening a specially crafted website in a browsing context,
an attacker could potentially exploit these to cause a denial of service,
obtain sensitive information, bypass security restrictions, cross-site
tracing, or execute arbitrary code.
Instructions: In general, a standard system update will make all the necessary changes.
Red Hat
firefox: Memory safety bugs fixed in Firefox 140 and Thunderbird 140
vendor_redhat·2025-06-24·CVSS 8.1
CVE-2025-6436 [HIGH] firefox: Memory safety bugs fixed in Firefox 140 and Thunderbird 140
firefox: Memory safety bugs fixed in Firefox 140 and Thunderbird 140
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.
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
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.
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Ad
Debian
CVE-2025-6436: firefox - Memory safety bugs present in Firefox 139 and Thunderbird 139. Some of these bug...
vendor_debian·2025·CVSS 8.1
CVE-2025-6436 [HIGH] CVE-2025-6436: firefox - Memory safety bugs present in Firefox 139 and Thunderbird 139. Some of these bug...
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.
Scope: local
sid: resolved (fixed in 140.0-1)
Mozilla
Mozilla Foundation Security Advisory 2025-54: CVE-2025-6436
vendor_mozilla·CVSS 8.1
CVE-2025-6436 [HIGH] Mozilla Foundation Security Advisory 2025-54: CVE-2025-6436
Mozilla Foundation Security Advisory 2025-54
CVE: CVE-2025-6436
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140
Mozilla
Mozilla Foundation Security Advisory 2025-51: CVE-2025-6436
vendor_mozilla·CVSS 8.1
CVE-2025-6436 [HIGH] Mozilla Foundation Security Advisory 2025-51: CVE-2025-6436
Mozilla Foundation Security Advisory 2025-51
CVE: CVE-2025-6436
Product: Firefox
Impact: high
Fixed in: Firefox 140
OSV
CVE-2025-6436: Memory safety bugs present in Firefox 139 and Thunderbird 139
osv·2025-06-24·CVSS 8.1
CVE-2025-6436 [HIGH] CVE-2025-6436: Memory safety bugs present in Firefox 139 and Thunderbird 139
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.
GHSA
GHSA-x8w4-qgw5-r433: Memory safety bugs present in Firefox 139 and Thunderbird 139
ghsa_unreviewed·2025-06-24
CVE-2025-6436 [MEDIUM] CWE-119 GHSA-x8w4-qgw5-r433: Memory safety bugs present in Firefox 139 and Thunderbird 139
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.
No detection rules found.
No public exploits indexed.
Checkpoint
30th June – Threat Intelligence Report
blogs_checkpoint·2025-06-30
CVE-2025-20281 30th June – Threat Intelligence Report
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## 30th June – Threat Intelligence Report
For the latest discoveries in cyber research for the week of 29th June, please download our Threat Intelligence Bulletin .
TOP ATTACKS AND BREACHES
Grocery giant Ahold Delhaize has disclosed a data breach that resulted in the theft of personal, financial, employment, and health information belonging to over 2.2 million individuals from its American business systems. The leaked data includes names, contact details, IDs, bank account numbers, and medical information . While
Bugzilla
CVE-2025-10158 rsync: Rsync: Out of bounds array access via negative index
bugzilla·2025-11-18·CVSS 4.3
CVE-2025-10158 [MEDIUM] CVE-2025-10158 rsync: Rsync: Out of bounds array access via negative index
CVE-2025-10158 rsync: Rsync: Out of bounds array access via negative index
A malicious client acting as the receiver of an rsync file transfer can trigger an out of bounds read of a heap based buffer, via a negative array index. The
malicious
rsync client requires at least read access to the remote rsync module in order to trigger the issue.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2026:6390 https://access.redhat.com/errata/RHSA-2026:6390
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2026:6436 https://access.redhat.com/errata/RHSA-2026:6436
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 10
Via RHSA-2026:6825 https://access.
Bugzilla
CVE-2025-6436 firefox: Memory safety bugs fixed in Firefox 140 and Thunderbird 140
bugzilla·2025-06-24·CVSS 8.1
CVE-2025-6436 [HIGH] CVE-2025-6436 firefox: Memory safety bugs fixed in Firefox 140 and Thunderbird 140
CVE-2025-6436 firefox: Memory safety bugs fixed in Firefox 140 and Thunderbird 140
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.
2025-06-24
Published