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CVE-2026-78376· NVD / CVE Program· CNA redhat

Webkitgtk: use-after-free of jscvalue function parameters

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.

HighCVSS 8.8 · v3.1—No exploit Fix available
Published
Aug 24, 2026
Updated
Sep 30, 2026
EPSS
0.3% · 19th percentile
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Report tools

JSON

Action score

35

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
8.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Affected systems

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Red Hat Red Hat Enterprise Linux 6

    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 7

    • all versionsunknown
    • all versionsaffected

  • Red Hat Red Hat Enterprise Linux 8

    • 0:2.54.0-1.el8_10 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 9

    • 0:2.54.0-1.el9_8 and laternot affected · rpm

  • WebKit WebKit

    • 2.21.1 and lateraffected · semver

  • WebKitGTK WebKitGTK

    • 2.21.1 and lateraffected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12webkit2gtkall versions—
Debian:12wpewebkitall versions—
Debian:13webkit2gtkbefore 2.54.0-1~deb13u12.54.0-1~deb13u1
Debian:14wpewebkitbefore 2.54.0-12.54.0-1

Same product

webkit: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-83596Webkitgtk: validate the full featurelist array once in opentypeverticaldata findfeature
    35Monitor
  • CVE-2016-9643The regex code in Webkit 2.4.11 allows remote attackers to cause a denial of service (memory consumption) as demonstrated in a large number
    31Monitor
  • CVE-2010-1766Off-by-one error in the WebSocketHandshake::readServerHandshake function in websockets/WebSocketHandshake.cpp in WebCore in WebKit before r5
    31Monitor
  • CVE-2016-9642JavaScriptCore in WebKit allows attackers to cause a denial of service (out-of-bounds heap read) via a crafted Javascript file.
    22Monitor
  • CVE-2009-3933WebKit before r50173, as used in Google Chrome before 3.0.195.32, allows remote attackers to cause a denial of service (CPU consumption) via
    21Monitor
  • CVE-2008-6059xml/XMLHttpRequest.cpp in WebCore in WebKit before r38566 does not properly restrict access from web pages to the (1) Set-Cookie and (2) Set
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:webkit2gtk2.54.0-1~deb13u1 · Debian:13Package registry (OSV)
debian:wpewebkit2.54.0-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records