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No exploitation reportedFix available

CVE-2021-21779

No exploitation reported by the sources we read.

  • Published2021-07-08
  • WeaknessCWE-416

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A use-after-free vulnerability exists in the way Webkit’s GraphicsContext handles certain events in WebKitGTK 2.30.4. A specially crafted web page can lead to a potential information leak and further memory corruption. A victim must be tricked into visiting a malicious web page to trigger this vulnerability.

Timeline

dates in UTC
  1. 2021-07-0812:15CVE publishedNVD

Versions per branch

NVD
Webkitgtk
BranchAffectedFixed in
2.30= 2.30.4no fix published
Fedoraproject fedora
BranchAffectedFixed in
33.x= 33no fix published
34.x= 34no fix published
Debian debian linux
BranchAffectedFixed in
10.0= 10.0no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • accountsserviceRocky Linux:8all versions · fixed in 0:0.6.55-2.el8
  • accountsserviceAlmaLinux:8all versions · fixed in 0.6.55-2.el8and 2 other packages
  • gdmRocky Linux:8all versions · fixed in 1:40.0-15.el8
  • gdmAlmaLinux:8all versions · fixed in 1:40.0-15.el8
  • gnome-autoarRocky Linux:8all versions · fixed in 0:0.2.3-2.el8
  • gnome-autoarRed Hat:enterprise_linux:8::appstreamall versions · fixed in 0:0.2.3-2.el8and 2 other packages
  • gnome-autoarAlmaLinux:8all versions · fixed in 0.2.3-2.el8
  • gnome-calculatorRocky Linux:8all versions · fixed in 0:3.28.2-2.el8

98 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-21779 Red Hat Product Security70 products fixed · 9 known affected

    webkitgtk: Use-after-free in WebCore::GraphicsContext leading to information leak and possibly code execution

    webkitgtk as a component of Red Hat Enterprise Linux 6 · webkitgtk-devel as a component of Red Hat Enterprise Linux 6 · webkitgtk-doc as a component of Red Hat Enterprise Linux 6 · +6 more

  • RHSA-2025:10364 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: webkitgtk4 security update

  • RHSA-2021:4381 Red Hat Product Security46 products fixed

    Red Hat Security Advisory: GNOME security, bug fix, and enhancement update

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2025:10364 · 13 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  2. Vendor fix Red Hat Product Security RHSA-2021:4381 · 46 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 GDM must be restarted for this update to take effect. The GNOME session must be restarted (log out, then log back in) for this update to take effect.
  3. No fix planned, says the vendor Red Hat Product Security CVE-2021-21779 · 9 productsOut of support scope

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.18.8read 2026-10-23
  • CNACVSS 3.06.8known since 2026-10-23
  • NVDCVSS 2.06.8read 2026-10-23
  • CNAweakness (CWE)CWE-416known since 2026-10-23
  • NVDweakness (CWE)CWE-416read 2026-10-23
  • FIRST EPSSEPSS score2.9 %2026-11-08
  • OSVaffected packages—
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
2021-07-08
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-fvf7-58x3-4492

Frequently asked questions

What is CVE-2021-21779?

A use-after-free vulnerability exists in the way Webkit’s GraphicsContext handles certain events in WebKitGTK 2.30.4. A specially crafted web page can lead to a potential information leak and further memory corruption. A victim must be tricked into visiting a malicious web page to trigger this vulnerability.

Is CVE-2021-21779 actively exploited?

Active exploitation of CVE-2021-21779 has not been confirmed. Its EPSS score was 2.9% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-21779?

CVE-2021-21779 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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