7.5

CVE-2026-8949: mozilla firefox Integer Overflow or Wraparound

CVSS: 7.5v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-8949CGA-68gg-f4mg-5v96CGA-mxh6-8fr2-847h
Published 19-05-2026Last modified 19-05-2026
Open JSON

Vulnerability summary

CVE-2026-8949 is a high (CVSS 7.5) Integer Overflow or Wraparound vulnerability in mozilla firefox. EPSS estimates a 0.60% chance of exploitation in the next 30 days, higher than 48% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.60%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 5
OPENSUSE-SU-2026:10813-1OPENSUSE-SU-2026:10863-1OPENSUSE-SU-2026:10864-1OPENSUSE-SU-2026:21168-1CGA-RRG6-GG3R-3W7Q

Timeline

  1. 19-05-2026
    PublishedVulnerability first disclosed.
  2. 19-05-2026
    Last modifiedVulnerability information updated.

Description

Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.60%

Chance of exploitation in the next 30 days

Percentile

48%

Versus all other CVEs

30-day change

+0.02 pp

From 0.58% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.60%

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

Ubuntu8 products
  • mozjs102All versions (No fix recorded)
  • mozjs115All versions (No fix recorded)
  • mozjs38All versions (No fix recorded)
  • mozjs52All versions (No fix recorded)
  • mozjs68All versions (No fix recorded)
Chainguard2 products
  • firefox< 140.11-r0
  • firefox-esr< 140.11-r0
Mozilla2 products
Wolfi1 product
  • firefox< 140.11-r0

4 vendors · 13 products

References

10 links