CVE-2026-83596: Webkitgtk: validate the full featurelist array once in opentypeverticaldata findfeature

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.3%

EPSS score, percentile 25.7 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

8.8 High

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (5)

Which versions are affected?

Affected

• 1.10.0
• 1.10.0

Unaffected 0:2.54.0-1.el7_9; 0:2.54.0-1.el8_10; 0:2.54.0-1.el9_8; 0:2.54.0-1.el9_2; 0:2.54.0-1.el9_6

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Workaround (from the CVE record)

Do not process or load untrusted web content with WebKitGTK. In Red Hat Enterprise Linux 7, the following packages require WebKitGTK4: evolution-data-server, glade, gnome-boxes, gnome-initial-setup, gnome-online-accounts, gnome-shell, shotwell, sushi and yelp. This vulnerability can only be exploited when these packages are installed in the system and being used via a graphical interface to process untrusted web content, via GNOME for example. In gnome-shell, the vulnerability can be exploited by an attacker from the local network without user interaction. To mitigate this vulnerability, consider removing these packages. Note that some of these packages are required by GNOME, removing them will also remove GNOME and other packages, breaking functionality. However, the server can still be used via the terminal interface. Additionally, WebKitGTK3 is not required by any package. Therefore, it can be removed without consequences or break of functionality.

Advisories and patches

• RHSA-2026:69098 (Vendor advisory)
• RHSA-2026:74084 (Vendor advisory)
• RHSA-2026:89821 (Vendor advisory)
• RHSA-2026:89822 (Vendor advisory)
• RHSA-2026:91631 (Vendor advisory)

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Versions not listed are: unaffected.

Versions not listed are: unaffected.

Versions not listed are: affected.

Versions not listed are: affected.

Versions not listed are: affected.

Versions not listed are: affected.

Versions not listed are: affected.

Versions not listed are: unknown.

Versions not listed are: unaffected.

Versions the record lists as unaffected: 0:2.54.0-1.el7_9, 0:2.54.0-1.el8_10, 0:2.54.0-1.el9_8, 0:2.54.0-1.el9_2, 0:2.54.0-1.el9_6.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

A flaw was found in WebKitGTK. Processing malicious web content can cause memory corruption due to improper memory handling.

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-83596 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 31 Aug 2026.
• The CVE record carries a CVSS v3.1 base score of 8.8 (High), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.3% (percentile 25.7), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact total.
• The credits in the CVE record name Google Big Sleep as finder.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

Webkitgtk: validate the full featurelist array once in opentypeverticaldata findfeature

A flaw was found in WebKitGTK. Processing malicious web content can cause memory corruption due to improper memory handling.

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline

Known exploited Red Hat vulnerabilities

• CVE-2015-3246: Red Hat Libuser Race Condition Vulnerability (added 26 Aug 2026)
• CVE-2015-5287: Red Hat Automatic Bug Reporting Tool Privilege Escalation Vulnerability (added 26 Aug 2026)
• CVE-2018-14667: Red Hat JBoss RichFaces Framework Expression Language Injection Vulnerability (added 28 Sep 2023)
• CVE-2021-3560: Red Hat Polkit Incorrect Authorization Vulnerability (added 12 May 2023)
• CVE-2021-4034: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability (added 27 Jun 2022)