8.8

CVE-2026-78376: webkit Use After Free

CVSS: 8.8v3.1HighAwaiting analysis
AliasesUBUNTU-CVE-2026-78376DEBIAN-CVE-2026-78376
Published 24-08-2026Last modified 30-09-2026
Open JSON

Vulnerability summary

CVE-2026-78376 is a high (CVSS 8.8) Use After Free vulnerability in webkit. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 19.7% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.29%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2
RHSA-2026:69098RHSA-2026:74084

Timeline

  1. 24-08-2026
    PublishedVulnerability first disclosed.
  2. 30-09-2026
    Last modifiedVulnerability information updated.

Description

A flaw was found in WebKitGTK. Processing malicious web content can cause a use-after-free issue due to improper memory handling and result in memory corruption.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.29%

Chance of exploitation in the next 30 days

Percentile

20%

Versus all other CVEs

30-day change

+0.01 pp

From 0.28% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.29%

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

Ubuntu5 products
  • qtwebkit-opensource-srcAll versions (No fix recorded)
  • qtwebkit-sourceAll versions (No fix recorded)
  • webkit2gtkAll versions (No fix recorded)
  • webkitgtkAll versions (No fix recorded)
  • wpewebkitAll versions (No fix recorded)
Debian2 products
  • webkit2gtkAll versions (No fix recorded) | < 2.54.0-1~deb13u1
  • wpewebkitAll versions (No fix recorded) | < 2.54.0-1
Webkit1 product
  • webkit≥ 2.21.1 (No fix recorded)
Webkitgtk1 product

4 vendors · 9 products

References

8 links