CVE-2021-26708

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.

Published: 2021-02-05 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-26708 is rated Moderate Risk (54.4/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.94%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-26708

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-15 1.07% 0.94% -0.14%
2 2026-03-02 1.00% 1.07% +0.07%
3 2026-02-23 — 1.00% —

Full EPSS history (35 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-26708

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.0 3.1 HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.0 5.9 [email protected]
6.9 2.0 MEDIUM
AV:L/AC:M/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 3.4 10.0 [email protected]

Weakness enumeration for CVE-2021-26708

OS Trackers for CVE-2021-26708

vendor priority summary link
debian not yet assigned CVE-2021-26708 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-26708
redhat high — https://access.redhat.com/security/cve/CVE-2021-26708
suse high CVE-2021-26708 severity important: SUSE including 40 source package names (bpftool-4.18.0-240.22.1.el8_3, kernel-4.18.0-240.22.1.el8_3, …), 272 product×package rows across 56 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (56 product lines)): Known Not Affected 246, Fixed 26. https://www.suse.com/security/cve/CVE-2021-26708/
ubuntu high CVE-2021-26708 high priority: Ubuntu including 124 source packages (linux, linux-allwinner, …), 1388 status rows across 13 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): DNE 1030, not-affected 203, released 115, ignored 40. https://ubuntu.com/security/CVE-2021-26708

Affected software / configurations for CVE-2021-26708

Vendor Product Version Raw CPE
linux linux_kernel >= 5.5, < 5.10.13 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
netapp aff_baseboard_management_controller — cpe:2.3:a:netapp:aff_baseboard_management_controller:-:*:*:*:*:*:*:*
netapp cloud_backup — cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
netapp fas_baseboard_management_controller — cpe:2.3:a:netapp:fas_baseboard_management_controller:-:*:*:*:*:*:*:*
netapp solidfire_\&_hci_management_node — cpe:2.3:a:netapp:solidfire_\&_hci_management_node:-:*:*:*:*:*:*:*
netapp solidfire_baseboard_management_controller — cpe:2.3:a:netapp:solidfire_baseboard_management_controller:-:*:*:*:*:*:*:*
netapp baseboard_management_controller_500f_firmware < 15.3 cpe:2.3:o:netapp:baseboard_management_controller_500f_firmware:*:*:*:*:*:*:*:*
netapp baseboard_management_controller_a250_firmware < 15.3 cpe:2.3:o:netapp:baseboard_management_controller_a250_firmware:*:*:*:*:*:*:*:*
netapp hci_h410c_firmware — cpe:2.3:o:netapp:hci_h410c_firmware:-:*:*:*:*:*:*:*

References for CVE-2021-26708

cvelogic Threat Intelligence