9.8

CVE-2026-16361: mozilla firefox

CVSS: 9.8v3.1CriticalAnalyzed
AliasesDEBIAN-CVE-2026-16361CGA-4xq3-jjxv-69m8CGA-qfr6-w44x-wwcf
Published 21-07-2026Last modified 24-07-2026
Open JSON

Vulnerability summary

CVE-2026-16361 is a critical (CVSS 9.8) vulnerability in mozilla firefox. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 23% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.32%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 31 · Related 9
MGASA-2026-0325MGASA-2026-0326OPENSUSE-SU-2026:11329-1OPENSUSE-SU-2026:11359-1OPENSUSE-SU-2026:21519-1RHSA-2026:47101

Timeline

  1. 21-07-2026
    PublishedVulnerability first disclosed.
  2. 24-07-2026
    Last modifiedVulnerability information updated.

Description

Memory safety bugs present in Thunderbird ESR 140.12. 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 ESR 115.38, Firefox ESR 140.13, and Thunderbird 140.13.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.32%

Chance of exploitation in the next 30 days

Percentile

23%

Versus all other CVEs

30-day change

0.00 pp

From 0.32% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.32%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard2 products
  • firefox-esr< 153.0-r0 | < 153.0-r1
  • firefox-esr-140< 140.13.0-r0
Debian2 products
  • firefox-esr< 140.13.0esr-1~deb12u1 | < 140.13.0esr-1~deb13u1 | < 140.13.0esr-1
  • thunderbird< 1:140.13.0esr-2~deb12u1 | < 1:140.13.0esr-2~deb13u1 | < 1:140.13.0esr-1
Mozilla2 products

3 vendors · 6 products

References

5 links