CVE-2026-78376Network attack vector

Memory corruption via unrooted JSCValue call arguments

Published Aug 24, 2026 · Updated Aug 25, 2026

Use-after-free in WebKitGTK 2.21.1 and later allows remote attackers to corrupt memory by inducing processing of malicious web content. JSCValue call helpers stored converted JSValueRef parameters in an unrooted Vector, so garbage collection during conversion could free earlier arguments before the call consumed them. Exploitation requires a host application to load attacker-controlled content; corruption can crash the process or enable code execution.

CVSS severity8.8
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in WebKitGTK 2.21.1 and later allows remote attackers to corrupt memory by inducing processing of malicious web content. JSCValue call helpers stored converted JSValueRef parameters in an unrooted Vector, so garbage collection during conversion could free earlier arguments before the call consumed them. Exploitation requires a host application to load attacker-controlled content; corruption can crash the process or enable code execution.

The record

CVE
CVE-2026-78376
Published
Aug 24, 2026
Updated
Aug 25, 2026
Vendor
The WebKitGTK Team
Product
WebKitGTK
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.21.1 <*

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The WebKitGTK Team · WebKitGTKversion=2.21.1 <*
Apple · WebKitversion=2.21.1 <*
389 Directory Server · Red Hat Enterprise Linux 7Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.

Published CVSS scores

8.8Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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