CVE-2026-6748Public exploitNetwork attack vector

Heap disclosure via mismatched image-row stride

Published Apr 21, 2026 · Updated Jul 15, 2026

Information disclosure in Firefox Web Codecs allows remote attackers to read heap bytes via crafted canvas frames. The copyPlane lambda in VideoFrame.cpp advances through an aligned image surface using packed row sizes, copying uninitialized padding into JavaScript-visible buffers. Exposure requires enabled WebCodecs in a secure scripting context and mismatched surface stride; Thunderbird also contains the flaw, but ordinary email reading disables scripting.

CVSS severity7.5

High

EPSS probability0.60%

Next 30 days · Oct 19, 2026

Known exploitationUnconfirmed

Based on sourced intelligence

Hinoki checkNot available

Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Get started

Summary

What happened

The record

CVE: CVE-2026-6748
Published: Apr 21, 2026
Updated: Jul 15, 2026

Vendor: libuser Project
Product: Red Hat Enterprise Linux 9
Classifications: CWE-457, CWE-824

Attack vector: network
Privileges: unauthenticated

Timeline

How it unfolded

Apr 21, 2026CVE publishedPublication date reported by the CVE source.
Jul 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork

Required privilegesunauthenticated

What is affected?

libuser Project · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.

libuser Project · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.

libuser Project · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.

libuser Project · Red Hat Enterprise Linux 7Affected versions are unavailable in this record.

Published CVSS scores

9.8UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

7.5OracleCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

7.5Red HatCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

6.5Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026

Latest reporting daySep 28, 2026

Latest daily unique IPsUnavailable

Prior 30-day averageUnavailable

SourceShadowserver honeypots (KEV)

Vectornetwork

Privilegesunauthenticated

Known exploitationUnconfirmed

Public exploitPublished

Weakness, pattern, technique

CWE-457Use of Uninitialized Variable

CWE-824Access of Uninitialized Pointer

Public exploit references

poc_videoframe_copyto_padding.htmlproof of concept · unverified

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Get started to see how Hinoki identifies affected software and validates exploitability in your environment.

Get started