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NVD / CVE Program· CNA mitre

CVE-2021-26708: A local privilege escalation was discovered in the Linux kernel before 5.10.13.

HighCVSS 7.0 · v3.1—Proof of concept Fix available

Noroxi assessment

Priority: Monitor (action score 28/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.6% (FIRST EPSS); higher than 76.1% of all records.
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: kernel-abi-whitelists (AlmaLinux:8) 4.18.0-240.22.1.el8_3; kernel-tools-libs-devel (AlmaLinux:8) 4.18.0-240.22.1.el8_3; linux (Debian:12) 5.10.13-1.

Low priority for now. Upgrade to kernel-abi-whitelists (AlmaLinux:8) 4.18.0-240.22.1.el8_3; kernel-tools-libs-devel (AlmaLinux:8) 4.18.0-240.22.1.el8_3; linux (Debian:12) 5.10.13-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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
Feb 5, 2021
Updated
Jun 16, 2026
EPSS
1.6% · 76th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.6%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

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Follow CVE-2021-26708

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  • when exploit code appears or is weaponized
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel
netappaff baseboard management controller
netappcloud backup
netappfas baseboard management controller
netappsolidfire \& hci management node
netappsolidfire baseboard management controller
netappbaseboard management controller 500f firmware
netapp500f
netappbaseboard management controller a250 firmware
netappa250
netapphci h410c firmware
netapphci h410c

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.5 and later · before 5.10.13
  • netapp aff baseboard management controllerall versions
  • netapp baseboard management controller 500f firmwarebefore 15.3
  • netapp baseboard management controller a250 firmwarebefore 15.3
  • netapp cloud backupall versions
  • netapp fas baseboard management controllerall versions
  • netapp hci h410c firmwareall versions
  • netapp solidfire & hci management nodeall versions
  • netapp solidfire baseboard management controllerall versions

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8kernel-abi-whitelistsbefore 4.18.0-240.22.1.el8_34.18.0-240.22.1.el8_3
AlmaLinux:8kernel-tools-libs-develbefore 4.18.0-240.22.1.el8_34.18.0-240.22.1.el8_3
Debian:12linuxbefore 5.10.13-15.10.13-1
Red Hat:enterprise_linux:8::baseosbpftoolbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseosbpftool-debuginfobefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernelbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-abi-whitelistsbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-corebefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debugbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debug-corebefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debug-debuginfobefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debug-develbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debug-modulesbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debug-modules-extrabefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debuginfobefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-aarch64before 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-ppc64lebefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-s390xbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-x86_64before 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-develbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-docbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-modulesbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-modules-extrabefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3
Red Hat:enterprise_linux:8::baseoskernel-toolsbefore 0:4.18.0-240.22.1.el8_30:4.18.0-240.22.1.el8_3

+28

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-3347Jan 29, 2021 · An issue was discovered in the Linux kernel through 5.10.11.
    31Monitor
  • ← EarlierCVE-2021-3348Feb 1, 2021 · nbd_add_socket in drivers/block/nbd.c in the Linux kernel through 5.10.12 has an ndb_queue_rq use-after-free that could be triggered by…
    28Monitor
  • Later →CVE-2020-16120Feb 10, 2021 · Unprivileged overlay + shiftfs read access
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:kernel-abi-whitelists4.18.0-240.22.1.el8_3 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-tools-libs-devel4.18.0-240.22.1.el8_3 · AlmaLinux:8Package registry (OSV)
debian:linux5.10.13-1 · Debian:12Package registry (OSV)
red hat:kernel-rt0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-core0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-core0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-debuginfo0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-devel0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-kvm0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-modules0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-modules-extra0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debuginfo0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debuginfo-common-x86_640:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-devel0:4.18.0-240.22.1.rt7.77.el8_3 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×3

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHub3 repositories2021-02-15 → 2026-08-07

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+10 d
  3. TodayNov 13, 2026+2107 d

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-667 · Improper Locking

CVSS vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records