Public proof of conceptFix available

CVE-2021-26708

Q: Is CVE-2021-26708 actively exploited?

Active exploitation of CVE-2021-26708 has not been confirmed. Its EPSS score was 1.6% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-26708?

CVE-2021-26708 has a CVSS v3 base score of 7 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

A public proof of concept exists; no exploitation attested.

Published2021-02-05
Fixed in5.10.13
WeaknessCWE-667

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A local privilege escalation was discovered in the Linux kernel before 5.10.13. Multiple race conditions in the AF_VSOCK implementation are caused by wrong locking in net/vmw_vsock/af_vsock.c. The race conditions were implicitly introduced in the commits that added VSOCK multi-transport support.

Timeline

dates in UTC

2021-02-0514:15CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-26708?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-26708?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Linux linux kernel

Branch	Affected	Fixed in	Source
5.x	≥ 5.5, < 5.10.13	5.10.13	NVD

Netapp aff baseboard management controller

Branch	Affected	Fixed in	Source
—	all versions	no fix published	NVD

Netapp baseboard management controller 500f firmwareversion to verify

Branch	Affected	Fixed in	Source
15.3	< 15.3	15.3	NVD

6 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Linux linux kernel to 5.10.13

Advisories and patches

www.openwall.comPatch
cdn.kernel.orgRelease Notes · Vendor Advisory
git.kernel.orgPatch · Vendor Advisory
security.netapp.comPatch
www.openwall.comPatch

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 3 repositories, unverifiedjordan9001/vsock_pocazpema/CVE-2021-26708kungaocode/vulnerability-analysis-

Sources

NVDCVSS 3.17read 2026-10-23
NVDCVSS 2.06.9read 2026-10-23
NVDweakness (CWE)CWE-667read 2026-10-23
FIRST EPSSEPSS score1.6 %2026-10-22
PoC-in-GitHubproof of concept3read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Published: 2021-02-05
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-26708?

Is CVE-2021-26708 actively exploited?

Active exploitation of CVE-2021-26708 has not been confirmed. Its EPSS score was 1.6% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-26708?

CVE-2021-26708 has a CVSS v3 base score of 7 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

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