CVE-2026-43503: In the Linux kernel, the following vulnerability has been resolved: net: skbuff: propagate shared-frag marker

Q: How do I fix CVE-2026-43503?

linux kernel: upgrade to 5.10.257, 5.15.208, 6.1.174, 6.6.141, 6.12.91, 6.18.33, 7.0.10. Exact commands for each OS are on this page.

Q: Is CVE-2026-43503 being exploited?

CVE-2026-43503 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-43503 affect?

CVE-2026-43503 affects linux kernel. Severity is high (CVSS 8.8). In the Linux kernel, the following vulnerability has been resolved: net: skbuff: propagate shared-frag marker through frag-transfer helpers Two frag-transfer helpers (__pskb_copy_fclone() and skb_shift()) fail to propagate the SKBFL_SHARE

Q: How urgent is CVE-2026-43503?

Priority 61/100. High severity; Public exploit reference; On your watchlist

This week

HIGH 8.8WATCHLISTUPGRADE

CVE-2026-43503 is a high-severity flaw (CVSS 8.8) affecting linux kernel. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: propagate shared-frag marker through frag-transfer helpers Two frag-transfer helpers (__pskb_copy_fclone() and skb_shift()) fail to propagate the SKBFL_SHARED_FRAG bit in skb_shinfo()->flags when moving frags from source to destination. __pskb_copy_fclone() defers the rest of the shinfo metadata to skb_copy_header() after copying frag descriptors, but that helper

Why this priority

High severity
Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	2.0% (top 19%)
CISA exploited list	No
Weakness	CWE-691, CWE-664
Published	2026-05-23
Last modified	2026-10-16

Publisher (CNA): kernel.org · Vendor: linux

Last updated 2026-10-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-23 12:17 UTCPublished CVE record published
2026-10-16 19:17 UTCUpdated Record last modified

linux linux kernel UPGRADE

Affected: >= 3.9 and < 5.10.257 · >= 5.11 and < 5.15.208 · >= 5.16 and < 6.1.174 · >= 6.2 and < 6.6.141 · >= 6.7 and < 6.12.91 · >= 6.13 and < 6.18.33 · >= 6.19 and < 7.0.10 · 7.1 rc1

Fixed in: 5.10.257, 5.15.208, 6.1.174, 6.6.141, 6.12.91, 6.18.33, 7.0.10

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

Fedora ELN · clash-meta · FIXED · 1.19.33-1.eln159 · FEDORA-2026-7dfb64c5e1 · source

sudo dnf upgrade --advisory=FEDORA-2026-7dfb64c5e1

Fedora 46 · vulkan-utility-libraries · FIXED · 1.4.363.0-1.fc46 · FEDORA-2026-994176daf5 · source

sudo dnf upgrade --advisory=FEDORA-2026-994176daf5

Debian 12 · linux · FIXED · 6.1.174-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.1.174-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · linux · FIXED · 6.12.90-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.12.90-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 10 · kernel · FIXED · kernel-6.12.0-211.16.1.el10_2

sudo dnf upgrade --advisory=RHSA-2026:19569 rpm -q kernel

RHEL 10.0 Extended Update Support · kernel · FIXED · kernel-6.12.0-55.75.1.el10_0

sudo dnf upgrade --advisory=RHSA-2026:20299 rpm -q kernel

RHEL 8 · kernel-rt · FIXED · kernel-rt-4.18.0-553.125.1.rt7.466.el8_10

sudo dnf upgrade --advisory=RHSA-2026:19664 rpm -q kernel-rt

RHEL 8 · kernel · FIXED · kernel-4.18.0-553.125.1.el8_10

sudo dnf upgrade --advisory=RHSA-2026:19666 rpm -q kernel

RHEL 8.4 Advanced Mission Critical Update Support · kernel · FIXED · kernel-4.18.0-305.192.1.el8_4

sudo dnf upgrade --advisory=RHSA-2026:20130 rpm -q kernel

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-1710 · source

sudo dnf update --advisory=ALAS2023-2026-1710

Amazon Linux 2 · see advisory · FIXED · ALAS2-2026-3307 · source

sudo yum update --advisory=ALAS2-2026-3307

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: 0xBlackash/CVE-2026-43503 (37 stars)
GitHub PoC: entra1337/DirtyClone (27 stars)
GitHub PoC: mooder1/dirtyclone-CVE-2026-43503 (17 stars)
Write-up: cert-portal.siemens.com/productcert/html/ssa-784472.html
Metasploit: Linux Kernel DirtyClone Local Privilege Escalation

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-43503?

linux kernel: upgrade to 5.10.257, 5.15.208, 6.1.174, 6.6.141, 6.12.91, 6.18.33, 7.0.10. Exact commands for each OS are on this page.

Is CVE-2026-43503 being exploited?

CVE-2026-43503 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-43503 affect?

CVE-2026-43503 affects linux kernel. Severity is high (CVSS 8.8). In the Linux kernel, the following vulnerability has been resolved: net: skbuff: propagate shared-frag marker through frag-transfer helpers Two frag-transfer helpers (__pskb_copy_fclone() and skb_shift()) fail to propagate the SKBFL_SHARE

How urgent is CVE-2026-43503?

Priority 61/100. High severity; Public exploit reference; On your watchlist

Software pages

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References

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