CVE-2021-36144: The polling timer handler in ACRN before 2.5 has a use-after-free for a freed virtio device, related to device

Q: How do I fix CVE-2021-36144?

acrn: upgrade to 2.5. Exact commands for each OS are on this page.

Q: Is CVE-2021-36144 being exploited?

CVE-2021-36144 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-2021-36144 affect?

CVE-2021-36144 affects acrn. Severity is high (CVSS 7.5). The polling timer handler in ACRN before 2.5 has a use-after-free for a freed virtio device, related to devicemodel/hw/pci/virtio/*.c.

Q: How urgent is CVE-2021-36144?

Priority 52/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADE

CVE-2021-36144 is a high-severity flaw (CVSS 7.5) affecting acrn. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The polling timer handler in ACRN before 2.5 has a use-after-free for a freed virtio device, related to devicemodel/hw/pci/virtio/*.c.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 38%)
CISA exploited list	No
Weakness	CWE-416
Published	2021-07-02
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: linux

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

Am I affected?

Timeline

2021-07-02 22:15 UTCPublished CVE record published
2026-06-17 03:58 UTCUpdated Record last modified

linux acrn UPGRADE

Affected: < 2.5

Fixed in: 2.5

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-2021-36144?

acrn: upgrade to 2.5. Exact commands for each OS are on this page.

Is CVE-2021-36144 being exploited?

CVE-2021-36144 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-2021-36144 affect?

CVE-2021-36144 affects acrn. Severity is high (CVSS 7.5). The polling timer handler in ACRN before 2.5 has a use-after-free for a freed virtio device, related to devicemodel/hw/pci/virtio/*.c.

How urgent is CVE-2021-36144?

Priority 52/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

CVE-2021-36148 HIGH 7.8 UPGRADE An issue was discovered in ACRN before 2.5
CVE-2021-36147 HIGH 7.5 UPGRADE An issue was discovered in ACRN before 2.5
CVE-2021-36146 HIGH 7.5 UPGRADE ACRN before 2.5 has a devicemodel/hw/pci/xhci.c NULL Pointer Dereference for a trb pointer.
CVE-2021-36145 HIGH 7.5 UPGRADE The Device Model in ACRN through 2.5 has a devicemodel/core/mem.c use-after-free for a freed rb_entry.
CVE-2021-36143 HIGH 7.5 UPGRADE ACRN before 2.5 has a hw/pci/virtio/virtio.c vq_endchains NULL Pointer Dereference.

References

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