CVE-2022-27666: A heap buffer overflow flaw was found in IPsec ESP transformation code in net/ipv4/esp4.c and net/ipv6/esp6.c

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HIGH 7.8WATCHLISTUPGRADEMITIGATEDOWNGRADE

CVE-2022-27666 is a high-severity flaw (CVSS 7.8) affecting linux kernel, fedora, virtualization. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A heap buffer overflow flaw was found in IPsec ESP transformation code in net/ipv4/esp4.c and net/ipv6/esp6.c. This flaw allows a local attacker with a normal user privilege to overwrite kernel heap objects and may cause a local privilege escalation threat.

Why this priority

High severity
EPSS top 7%: very likely to be exploited
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	5.5% (top 7%)
CISA exploited list	No
Weakness	CWE-787
Published	2022-03-23
Last modified	2026-09-01

Publisher (CNA): MITRE · Vendor: fedoraproject · linux · netapp · redhat

Last updated 2026-09-01 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-03-23 06:15 UTCPublished CVE record published
2026-09-01 18:05 UTCUpdated Record last modified

linux linux kernel UPGRADE

Affected: >= 4.11 and < 4.14.274 · >= 4.15 and < 4.19.237 · >= 4.20 and < 5.4.188 · >= 5.5 and < 5.10.108 · >= 5.11 and < 5.15.29 · >= 5.16 and < 5.16.15 · 5.17 rc1 · 5.17 rc2

Fixed in: 4.14.274, 4.19.237, 5.4.188, 5.10.108, 5.15.29, 5.16.15

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.

fedoraproject fedora MITIGATE

Affected: 34 · 35

Fixed in: no fixed release known

Safe to downgrade to: a release before 34

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.

redhat virtualization DOWNGRADE

Affected: 4.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.0

1. Check installed version

apt-cache policy virtualization || rpm -q virtualization || virtualization --version

2. No fixed release: DOWNGRADE to a release before 4.0 (Debian / Ubuntu)

apt-cache madison virtualization sudo apt install virtualization=<VERSION_BEFORE_4.0> sudo apt-mark hold virtualization

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list virtualization sudo dnf downgrade virtualization-<VERSION_BEFORE_4.0> sudo dnf versionlock add virtualization

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

redhat enterprise linux MITIGATE

Affected: 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

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.

netapp h300s 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 h500s 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.

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-2022-27666?

linux kernel: upgrade to 4.14.274, 4.19.237, 5.4.188, 5.10.108, 5.15.29, 5.16.15; fedora: mitigate or apply the listed mitigation; virtualization: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2022-27666 being exploited?

CVE-2022-27666 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-2022-27666 affect?

CVE-2022-27666 affects linux kernel, fedora, virtualization. Severity is high (CVSS 7.8). A heap buffer overflow flaw was found in IPsec ESP transformation code in net/ipv4/esp4.c and net/ipv6/esp6.c. This flaw allows a local attacker with a normal user privilege to overwrite kernel heap objects and may cause a local privilege e

How urgent is CVE-2022-27666?

Priority 55/100. High severity; EPSS top 7%: very likely to be exploited; On your watchlist

Software pages

Linux kernel vulnerabilities

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References

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