BlackTreeCVE Intelligence
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Full vulnerability report · 2022
CVE-2021-4159High confidence

A vulnerability was found in the Linux kernel's EBPF verifier when handling internal data structures

Unknown · kernel

4.4MediumCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Low, lowered one band.downgradedsince 3 Aug 2024

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 0.25% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Unknown kernel and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: No default targetRemediation target: Normal maintenance

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

5 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.7.6-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.7.6-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.7.6-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.7.6-1Debian Security Tracker ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivelinux-raspi-realtimeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical Ubuntu Security ↗Source updated 5 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2021-4159 · CSAF 2.0 · revision 28 · interimSUSE Product Security TeamCVE-2021-4159
15 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • SLES 15 SP1 CHOST Images for Amazon EC2
  • SLES 15 SP2 CHOST Images for Amazon EC2
  • SLES 15 SP3 CHOST Images for Amazon EC2
  • SLES 15 SP4 CHOST Images for Amazon EC2
  • SLES 15 SP5 CHOST Images for Amazon EC2
  • SLES 15 SP1 CHOST Images for Google
  • SLES 15 SP2 CHOST Images for Google
  • SLES 15 SP3 CHOST Images for Google
  • SLES 15 SP4 CHOST Images for Google
  • SLES 15 SP5 CHOST Images for Google
  • SLES 15 SP1 CHOST Images for Microsoft Azure
  • SLES 15 SP2 CHOST Images for Microsoft Azure
Summary
A vulnerability was found in the Linux kernel's EBPF verifier when handling internal data structures. Internal memory locations could be returned to userspace. A local attacker with the permissions to insert eBPF code to the kernel can use this to leak internal kernel memory details defeating some of the exploit mitigations in place for the kernel.
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2021-34027

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

A vulnerability was found in the Linux kernel's EBPF verifier when handling internal data structures. Internal memory locations could be returned to userspace. A local attacker with the permissions to insert eBPF code to the kernel can use this to leak internal kernel memory details defeating some of the exploit mitigations in place for the kernel.

What

A vulnerability was found in the Linux kernel's EBPF verifier when handling internal data structures. Internal memory locations could be returned to userspace. A local attacker with the permissions to insert eBPF code to the kernel can use this to leak internal kernel memory details defeating some of the exploit mitigations in place for the kernel.

Why

When trying to keep information confidential, an attacker can often infer some of the information by using statistics.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

A vulnerability was found in the Linux kernel's EBPF verifier when handling internal data structures. Internal memory locations could be returned to userspace. A local attacker with the permissions to insert eBPF code to the kernel can use this to leak internal kernel memory details defeating some of the exploit mitigations in place for the kernel.

Why

When trying to keep information confidential, an attacker can often infer some of the information by using statistics.

How

An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → Exposure of Sensitive Information Through Data Queries → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
High: elevated access is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-202 ↗

CWE-202: Exposure of Sensitive Information Through Data Queries. When trying to keep information confidential, an attacker can often infer some of the information by using statistics.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
CWE-202
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2022-1207Linux Kernel: Mehrere Schwachstellen ermöglichen Offenlegung von Informationen

Ein entfernter, anonymer oder lokaler Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um Informationen offenzulegen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20220831Security Bulletin 31 Aug 2022

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 31 Aug 2022, published on 31 August 2022. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0529Multiples vulnérabilités dans le noyau Linux de SUSE

SUSE SUSE-SU-2025:01995-1 du 18 juin 2025 https://www.suse.com/support/update/announcement/2025/suse-su-202501995-1 Bulletin de sécurité SUSE SUSE-SU-2025:02000-1 du 18 juin 2025 https://www.suse.com/support/update/announcement/2025/suse-su-202502000-1 Référence CVE CVE-2020-36790 https://www.cve.org/CVERecord?id=CVE-2020-36790 Référence CVE CVE-2020-36791 https://www.cve.org/CVERecord?id=CVE-2020-36791 Référence CVE CVE-2021-20320 https://www.cve.org/CVERecord?id=CVE-2021-20320 Référence CVE CVE-2021-32399 https://www.cve.org/CVERecord?id=CVE-2021-32399 Référence CVE CVE-2021-3743 https://www.cve.org/CVERecord?id=CVE-2021-3743 Référence CVE CVE-2021-4159 https://www.cve.org/CVERecord?id=CVE-2021-4159 Référence CVE CVE-2021-47100 https://www.cve.org/CVERecord?id=CVE-2021-47100 Référence CVE CVE-2021-47170 https://www.cve.org/CVERecord?id=CVE-2021-47170 Référence CVE CVE-2021-47220 https://www.cve.org/CVERecord?id=CVE-2021-47220 Référence CVE CVE-2021-47229 https://www.cve.org/CVERecord?id=CVE-2021-47229 Référence CVE CVE-2021-47231 https://www.cve.org/CVERecord?id=CVE-2021-47231 Référence CVE CVE-2021-47236 https://www.cve.org/CVERecord?id=CVE-2021-47236 Référence CVE CVE-2021-47239 https://www.cve.org/CVERecord?id=CVE-2021-47239 Référence CVE CVE-2021-47240 https://www.cve.org/CVERecord?id=C

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-0027Multiples vulnérabilités dans le noyau Linux d'Ubuntu

buntu du 10 janvier 2023 https://ubuntu.com/security/notices/USN-5793-3 Bulletin de sécurité Ubuntu du 10 janvier 2023 https://ubuntu.com/security/notices/USN-5791-3 Bulletin de sécurité Ubuntu du 10 janvier 2023 https://ubuntu.com/security/notices/USN-5793-4 Bulletin de sécurité Ubuntu du 11 janvier 2023 https://ubuntu.com/security/notices/USN-5799-1 Bulletin de sécurité Ubuntu du 12 janvier 2023 https://ubuntu.com/security/notices/USN-5802-1 Bulletin de sécurité Ubuntu du 13 janvier 2023 https://ubuntu.com/security/notices/USN-5803-1 Bulletin de sécurité Ubuntu du 13 janvier 2023 https://ubuntu.com/security/notices/USN-5804-1 Référence CVE CVE-2021-4159 https://www.cve.org/CVERecord?id=CVE-2021-4159 Référence CVE CVE-2022-0171 https://www.cve.org/CVERecord?id=CVE-2022-0171 Référence CVE CVE-2022-20421 https://www.cve.org/CVERecord?id=CVE-2022-20421 Référence CVE CVE-2022-2663 https://www.cve.org/CVERecord?id=CVE-2022-2663 Référence CVE CVE-2022-3061 https://www.cve.org/CVERecord?id=CVE-2022-3061 Référence CVE CVE-2022-3303 https://www.cve.org/CVERecord?id=CVE-2022-3303 Référence CVE CVE-2022-3541 https://www.cve.org/CVERecord?id=CVE-2022-3541 Référence CVE CVE-2022-3543 https://www.cve.org/CVERecord?id=CVE-2022-3543 Référence CVE CVE-2022-3544 https://www.cve.org/CVERecord?id=CVE-2022-3544

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-968Multiples vulnérabilités dans le noyau Linux d'Ubuntu

De multiples vulnérabilités ont été découvertes dans le noyau Linux d'Ubuntu. Elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, un déni de service à distance et une atteinte à la confidentialité des données.

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-919Multiples vulnérabilités dans le noyau Linux d'Ubuntu

De multiples vulnérabilités ont été découvertes dans le noyau Linux d'Ubuntu. Elles permettent à un attaquant de provoquer une exécution de code arbitraire, un déni de service à distance et une atteinte à la confidentialité des données.

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-895Multiples vulnérabilités dans le noyau Linux d'Ubuntu

De multiples vulnérabilités ont été découvertes dans le noyau Linux d'Ubuntu. Elles permettent à un attaquant de provoquer une exécution de code arbitraire, un déni de service à distance et une atteinte à la confidentialité des données.

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-875Multiples vulnérabilités dans le noyau Linux de Debian

à 4.19.260-1 Résumé De multiples vulnérabilités ont été découvertes dans le noyau Linux de Debian. Elles permettent à un attaquant de provoquer un déni de service à distance, une atteinte à la confidentialité des données et une élévation de privilèges. Solution Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation). Documentation Bulletin de sécurité Debian du 02 octobre 2022 https://www.debian.org/lts/security/2022/dla-3131 Référence CVE CVE-2021-33655 https://www.cve.org/CVERecord?id=CVE-2021-33655 Référence CVE CVE-2021-33656 https://www.cve.org/CVERecord?id=CVE-2021-33656 Référence CVE CVE-2021-4159 https://www.cve.org/CVERecord?id=CVE-2021-4159 Référence CVE CVE-2022-1462 https://www.cve.org/CVERecord?id=CVE-2022-1462 Référence CVE CVE-2022-1679 https://www.cve.org/CVERecord?id=CVE-2022-1679 Référence CVE CVE-2022-2153 https://www.cve.org/CVERecord?id=CVE-2022-2153 Référence CVE CVE-2022-2318 https://www.cve.org/CVERecord?id=CVE-2022-2318 Référence CVE CVE-2022-2586 https://www.cve.org/CVERecord?id=CVE-2022-2586 Référence CVE CVE-2022-2588 https://www.cve.org/CVERecord?id=CVE-2022-2588 Référence CVE CVE-2022-26365 https://www.cve.org/CVERecord?id=CVE-2022-26365 Référence CVE CVE-2022-26373 https://www.cve.org/CVERecord?id=CVE-2022-2637

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-144Multiples vulnérabilités dans le noyau Linux de SUSE

g/CVERecord?id=CVE-2021-33098 Référence CVE CVE-2021-3564 https://www.cve.org/CVERecord?id=CVE-2021-3564 Référence CVE CVE-2021-39648 https://www.cve.org/CVERecord?id=CVE-2021-39648 Référence CVE CVE-2021-39657 https://www.cve.org/CVERecord?id=CVE-2021-39657 Référence CVE CVE-2021-39685 https://www.cve.org/CVERecord?id=CVE-2021-39685 Référence CVE CVE-2021-4002 https://www.cve.org/CVERecord?id=CVE-2021-4002 Référence CVE CVE-2021-4083 https://www.cve.org/CVERecord?id=CVE-2021-4083 Référence CVE CVE-2021-4135 https://www.cve.org/CVERecord?id=CVE-2021-4135 Référence CVE CVE-2021-4149 https://www.cve.org/CVERecord?id=CVE-2021-4149 Référence CVE CVE-2021-4159 https://www.cve.org/CVERecord?id=CVE-2021-4159 Référence CVE CVE-2021-4197 https://www.cve.org/CVERecord?id=CVE-2021-4197 Référence CVE CVE-2021-4202 https://www.cve.org/CVERecord?id=CVE-2021-4202 Référence CVE CVE-2021-43975 https://www.cve.org/CVERecord?id=CVE-2021-43975 Référence CVE CVE-2021-43976 https://www.cve.org/CVERecord?id=CVE-2021-43976 Référence CVE CVE-2021-44733 https://www.cve.org/CVERecord?id=CVE-2021-44733 Référence CVE CVE-2021-45095 https://www.cve.org/CVERecord?id=CVE-2021-45095 Référence CVE CVE-2021-45486 https://www.cve.org/CVERecord?id=CVE-2021-45486 Référence CVE CVE-2022-0286 https://www.cve.org/CVERecord?id=CVE-20

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-141Multiples vulnérabilités dans le noyau Linux de SUSE

rg/CVERecord?id=CVE-2021-3564 Référence CVE CVE-2021-39648 https://www.cve.org/CVERecord?id=CVE-2021-39648 Référence CVE CVE-2021-39657 https://www.cve.org/CVERecord?id=CVE-2021-39657 Référence CVE CVE-2021-39685 https://www.cve.org/CVERecord?id=CVE-2021-39685 Référence CVE CVE-2021-4002 https://www.cve.org/CVERecord?id=CVE-2021-4002 Référence CVE CVE-2021-4083 https://www.cve.org/CVERecord?id=CVE-2021-4083 Référence CVE CVE-2021-4135 https://www.cve.org/CVERecord?id=CVE-2021-4135 Référence CVE CVE-2021-4149 https://www.cve.org/CVERecord?id=CVE-2021-4149 Référence CVE CVE-2021-4155 https://www.cve.org/CVERecord?id=CVE-2021-4155 Référence CVE CVE-2021-4159 https://www.cve.org/CVERecord?id=CVE-2021-4159 Référence CVE CVE-2021-4197 https://www.cve.org/CVERecord?id=CVE-2021-4197 Référence CVE CVE-2021-4202 https://www.cve.org/CVERecord?id=CVE-2021-4202 Référence CVE CVE-2021-43975 https://www.cve.org/CVERecord?id=CVE-2021-43975 Référence CVE CVE-2021-43976 https://www.cve.org/CVERecord?id=CVE-2021-43976 Référence CVE CVE-2021-44733 https://www.cve.org/CVERecord?id=CVE-2021-44733 Référence CVE CVE-2021-45095 https://www.cve.org/CVERecord?id=CVE-2021-45095 Référence CVE CVE-2021-45485 https://www.cve.org/CVERecord?id=CVE-2021-45485 Référence CVE CVE-2021-45486 https://www.cve.org/CVERecord?id=CVE-2

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-020319Linux の Linux Kernel 他複数ベンダの製品における脆弱性

Linux の Linux Kernel 他複数ベンダの製品には、不特定の脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 24 Aug 2022 · Last source change 3 Aug 2024, 17:16 UTC · CWE-202 · Exposure of Sensitive Information Through Data Queries

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2021-34027
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · SUSE Product Security Team
CWE sourceCNA
NVD statusNVD modified after enrichment

Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2021-34027↗Vendor CSAF · SUSE Product Security Team↗Patch or update reference↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2021-4159 · cve.blacktree.nl