CVE-2021-22600: Linux Kernel Privilege Escalation Vulnerability

Q: How do I fix CVE-2021-22600?

8300 firmware: mitigate or apply the listed mitigation; 8700 firmware: mitigate or apply the listed mitigation; a400 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2021-22600 being exploited?

Yes. CVE-2021-22600 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

Q: What does CVE-2021-22600 affect?

CVE-2021-22600 affects 8300 firmware, 8700 firmware, a400 firmware. Severity is medium (CVSS 6.6). A double free bug in packet_set_ring() in net/packet/af_packet.c can be exploited by a local user through crafted syscalls to escalate privileges or deny service. We recommend upgrading kernel past the effected versions or rebuilding past e

Q: How urgent is CVE-2021-22600?

Priority 77/100. EPSS top 6%: very likely to be exploited; Exploited in the wild (CISA KEV); On your watchlist

Patch now

MEDIUM 6.6EXPLOITEDWATCHLISTMITIGATEMITIGATEMITIGATE

CVE-2021-22600 is a medium-severity flaw (CVSS 6.6) affecting 8300 firmware, 8700 firmware, a400 firmware, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A double free bug in packet_set_ring() in net/packet/af_packet.c can be exploited by a local user through crafted syscalls to escalate privileges or deny service. We recommend upgrading kernel past the effected versions or rebuilding past ec6af094ea28f0f2dda1a6a33b14cd57e36a9755

Why this priority

EPSS top 6%: very likely to be exploited
Exploited in the wild (CISA KEV)
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.6 (Medium)
Attack vector	Local
Attack complexity	High
Privileges needed	Low
User interaction	Required
EPSS exploit chance	6.6% (top 6%)
CISA exploited list	Yes, fix due 2022-05-02
Weakness	CWE-415
Published	2022-01-26
Last modified	2026-06-17

Publisher (CNA): Google Inc. · Vendor: debian · linux · netapp

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-01-26 14:15 UTCPublished CVE record published
2022-04-11Exploited Added to the CISA Known Exploited Vulnerabilities list
2022-05-02Deadline CISA due date for US federal agencies to patch
2026-06-17 03:37 UTCUpdated Record last modified

netapp 8300 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

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.

netapp 8700 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

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.

netapp a400 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

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.

netapp c400 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

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.

linux linux kernel UPGRADE

Affected: >= 4.14.175 and < 4.14.259 · >= 4.19.114 and < 4.19.222 · >= 5.4.29 and < 5.4.168 · >= 5.5.14 and < 5.10.88 · >= 5.11 and < 5.15.11

Fixed in: 4.14.259, 4.19.222, 5.4.168, 5.10.88, 5.15.11

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.

debian debian linux MITIGATE

Affected: 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

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

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · nemo · FIXED · 6.8.0-1.fc46 · FEDORA-2026-0edead723f · source

sudo dnf upgrade --advisory=FEDORA-2026-0edead723f

Fedora ELN · composer · FIXED · 2.11.1-1.eln159 · FEDORA-2026-cb4f992456 · source

sudo dnf upgrade --advisory=FEDORA-2026-cb4f992456

Ubuntu 22.04 · linux · NOT AFFECTED

Ubuntu 20.04 · linux · FIXED · 5.4.0-100.113

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.4.0-100.113" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · linux · NOT AFFECTED

Ubuntu 24.10 · linux · NOT AFFECTED

Ubuntu 25.04 · linux · NOT AFFECTED

Debian 12 · linux · FIXED · 5.15.15-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.15.15-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · linux · FIXED · 5.15.15-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.15.15-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 6 · kernel · NOT AFFECTED

RHEL 7 · kernel · NOT AFFECTED

RHEL 7 · kernel-rt · NOT AFFECTED

RHEL 8 · kernel · NOT AFFECTED

RHEL 8 · kernel-rt · NOT AFFECTED

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: sendINUX/CVE-2021-22600__DirtyPagetable (1 stars)
GitHub PoC: Chinmay1743/af_packet.c (1 stars)
Write-up: git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=ec6af094ea28f0f2dda1a

Verify at the official source NVD · CVE Program · CISA KEV catalog · 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-2021-22600?

8300 firmware: mitigate or apply the listed mitigation; 8700 firmware: mitigate or apply the listed mitigation; a400 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-22600 being exploited?

Yes. CVE-2021-22600 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

What does CVE-2021-22600 affect?

CVE-2021-22600 affects 8300 firmware, 8700 firmware, a400 firmware. Severity is medium (CVSS 6.6). A double free bug in packet_set_ring() in net/packet/af_packet.c can be exploited by a local user through crafted syscalls to escalate privileges or deny service. We recommend upgrading kernel past the effected versions or rebuilding past e

How urgent is CVE-2021-22600?

Priority 77/100. EPSS top 6%: very likely to be exploited; Exploited in the wild (CISA KEV); On your watchlist

Software pages

Linux kernel vulnerabilities · Debian vulnerabilities

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References

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