CVE-2021-33634: iSulad uses the lcr+lxc runtime (default) to run malicious images, which can cause DOS.

Routine

MEDIUM 6.3UPGRADE

CVE-2021-33634 is a medium-severity flaw (CVSS 6.3) affecting icr. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

iSulad uses the lcr+lxc runtime (default) to run malicious images, which can cause DOS.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.3 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 89%)
CISA exploited list	No
Weakness	CWE-665
Published	2023-10-29
Last modified	2026-06-17

Publisher (CNA): openEuler · Vendor: openeuler

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

Am I affected?

Timeline

2023-10-29 08:15 UTCPublished CVE record published
2026-06-17 03:54 UTCUpdated Record last modified

openeuler icr UPGRADE

Affected: < 2.0.9-6 · >= 2.1.0 and < 2.1.2-3

Fixed in: 2.0.9-6, 2.1.2-3

Safe to downgrade to: a release before 2.1.0

1. Check installed version

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

2. UPGRADE to 2.0.9-6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade icr

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade icr

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.1.0 (Debian / Ubuntu)

apt-cache madison icr sudo apt install icr=<VERSION_BEFORE_2.1.0> sudo apt-mark hold icr

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list icr sudo dnf downgrade icr-<VERSION_BEFORE_2.1.0> sudo dnf versionlock add icr

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.

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-2021-33634?

icr: upgrade to 2.0.9-6, 2.1.2-3. Exact commands for each OS are on this page.

Is CVE-2021-33634 being exploited?

CVE-2021-33634 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-2021-33634 affect?

CVE-2021-33634 affects icr. Severity is medium (CVSS 6.3). iSulad uses the lcr+lxc runtime (default) to run malicious images, which can cause DOS.

How urgent is CVE-2021-33634?

Priority 25/100. No elevated risk signals yet.

References

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