BlackTreeCVE Intelligence
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Full vulnerability report · 2021
CVE-2021-38208High confidence

n/a — NULL Pointer Dereference

Unknown · Unknown

5.5MediumCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance. 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:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 0.49% 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.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Unknown Unknown 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: As exposure requiresRemediation target: Within 365 days

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.5.10.46-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.10.46-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.10.46-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.10.46-1Debian 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
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-2021-24666

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 public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance. 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

net/nfc/llcp_sock.c in the Linux kernel before 5.12.10 allows local unprivileged users to cause a denial of service (NULL pointer dereference and BUG) by making a getsockname call after a certain type of failure of a bind call.

What

net/nfc/llcp_sock.c in the Linux kernel before 5.12.10 allows local unprivileged users to cause a denial of service (NULL pointer dereference and BUG) by making a getsockname call after a certain type of failure of a bind call.

Why

The product dereferences a pointer that it expects to be valid but is NULL.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.

What

net/nfc/llcp_sock.c in the Linux kernel before 5.12.10 allows local unprivileged users to cause a denial of service (NULL pointer dereference and BUG) by making a getsockname call after a certain type of failure of a bind call.

Why

The product dereferences a pointer that it expects to be valid but is NULL.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.

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.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
local access → NULL Pointer Dereference → disrupt the affected service
Attack surface
Local
Privileges required
Low: a basic authenticated account 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-476 ↗

CWE-476: NULL Pointer Dereference. The product dereferences a pointer that it expects to be valid but is NULL.

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:L/UI:N/S:U/C:N/I:N/A:H

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.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
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.
Denial of serviceCWE-476Public exploit reference
A

Official authority intelligence

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

Cyber Security Agency of Singapore · English · CSA-SB-20210811Security Bulletin 11 Aug 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 11 Aug 2021, published on 11 August 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-569Multiples vulnérabilités dans le noyau Linux de SUSE

2/suse-su-20222111-1/ Référence CVE CVE-2017-13695 https://www.cve.org/CVERecord?id=CVE-2017-13695 Référence CVE CVE-2018-7755 https://www.cve.org/CVERecord?id=CVE-2018-7755 Référence CVE CVE-2019-19377 https://www.cve.org/CVERecord?id=CVE-2019-19377 Référence CVE CVE-2019-20811 https://www.cve.org/CVERecord?id=CVE-2019-20811 Référence CVE CVE-2020-26541 https://www.cve.org/CVERecord?id=CVE-2020-26541 Référence CVE CVE-2021-20292 https://www.cve.org/CVERecord?id=CVE-2021-20292 Référence CVE CVE-2021-20321 https://www.cve.org/CVERecord?id=CVE-2021-20321 Référence CVE CVE-2021-33061 https://www.cve.org/CVERecord?id=CVE-2021-33061 Référence CVE CVE-2021-38208 https://www.cve.org/CVERecord?id=CVE-2021-38208 Référence CVE CVE-2021-39711 https://www.cve.org/CVERecord?id=CVE-2021-39711 Référence CVE CVE-2021-43389 https://www.cve.org/CVERecord?id=CVE-2021-43389 Référence CVE CVE-2022-1011 https://www.cve.org/CVERecord?id=CVE-2022-1011 Référence CVE CVE-2022-1184 https://www.cve.org/CVERecord?id=CVE-2022-1184 Référence CVE CVE-2022-1353 https://www.cve.org/CVERecord?id=CVE-2022-1353 Référence CVE CVE-2022-1419 https://www.cve.org/CVERecord?id=CVE-2022-1419 Référence CVE CVE-2022-1516 https://www.cve.org/CVERecord?id=CVE-2022-1516 Référence CVE CVE-2022-1652 https://www.cve.org/CVERecord?id=CVE-2022-16

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-567Multiples vulnérabilités dans le noyau Linux de SUSE

2104-1 du 16 juin 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20222104-1/ Référence CVE CVE-2017-13695 https://www.cve.org/CVERecord?id=CVE-2017-13695 Référence CVE CVE-2019-19377 https://www.cve.org/CVERecord?id=CVE-2019-19377 Référence CVE CVE-2019-20811 https://www.cve.org/CVERecord?id=CVE-2019-20811 Référence CVE CVE-2020-26541 https://www.cve.org/CVERecord?id=CVE-2020-26541 Référence CVE CVE-2021-20292 https://www.cve.org/CVERecord?id=CVE-2021-20292 Référence CVE CVE-2021-20321 https://www.cve.org/CVERecord?id=CVE-2021-20321 Référence CVE CVE-2021-33061 https://www.cve.org/CVERecord?id=CVE-2021-33061 Référence CVE CVE-2021-38208 https://www.cve.org/CVERecord?id=CVE-2021-38208 Référence CVE CVE-2021-39711 https://www.cve.org/CVERecord?id=CVE-2021-39711 Référence CVE CVE-2021-43389 https://www.cve.org/CVERecord?id=CVE-2021-43389 Référence CVE CVE-2022-0168 https://www.cve.org/CVERecord?id=CVE-2022-0168 Référence CVE CVE-2022-1011 https://www.cve.org/CVERecord?id=CVE-2022-1011 Référence CVE CVE-2022-1158 https://www.cve.org/CVERecord?id=CVE-2022-1158 Référence CVE CVE-2022-1184 https://www.cve.org/CVERecord?id=CVE-2022-1184 Référence CVE CVE-2022-1353 https://www.cve.org/CVERecord?id=CVE-2022-1353 Référence CVE CVE-2022-1419 https://www.cve.org/CVERecord?id=CVE-2022-14

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-555Multiples vulnérabilités dans le noyau Linux de SUSE

ord?id=CVE-2018-20784 Référence CVE CVE-2018-7755 https://www.cve.org/CVERecord?id=CVE-2018-7755 Référence CVE CVE-2019-19377 https://www.cve.org/CVERecord?id=CVE-2019-19377 Référence CVE CVE-2019-20811 https://www.cve.org/CVERecord?id=CVE-2019-20811 Référence CVE CVE-2020-10769 https://www.cve.org/CVERecord?id=CVE-2020-10769 Référence CVE CVE-2021-20292 https://www.cve.org/CVERecord?id=CVE-2021-20292 Référence CVE CVE-2021-20321 https://www.cve.org/CVERecord?id=CVE-2021-20321 Référence CVE CVE-2021-28688 https://www.cve.org/CVERecord?id=CVE-2021-28688 Référence CVE CVE-2021-33061 https://www.cve.org/CVERecord?id=CVE-2021-33061 Référence CVE CVE-2021-38208 https://www.cve.org/CVERecord?id=CVE-2021-38208 Référence CVE CVE-2021-39711 https://www.cve.org/CVERecord?id=CVE-2021-39711 Référence CVE CVE-2021-43389 https://www.cve.org/CVERecord?id=CVE-2021-43389 Référence CVE CVE-2022-0168 https://www.cve.org/CVERecord?id=CVE-2022-0168 Référence CVE CVE-2022-1011 https://www.cve.org/CVERecord?id=CVE-2022-1011 Référence CVE CVE-2022-1184 https://www.cve.org/CVERecord?id=CVE-2022-1184 Référence CVE CVE-2022-1353 https://www.cve.org/CVERecord?id=CVE-2022-1353 Référence CVE CVE-2022-1419 https://www.cve.org/CVERecord?id=CVE-2022-1419 Référence CVE CVE-2022-1516 https://www.cve.org/CVERecord?id=CVE-2022-15

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-462Multiples vulnérabilités dans le noyau Linux de SUSE

De multiples vulnérabilités ont été découvertes dans le noyau Linux de SUSE. Certaines d'entre elles permettent à un attaquant de provoquer un problème de sécurité non spécifié par l'éditeur, un déni de service et un contournement de la politique de sécurité.

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-265Multiples vulnérabilités dans le noyau Linux de Ubuntu

rg/CVERecord?id=CVE-2021-3483 Référence CVE CVE-2021-3506 https://www.cve.org/CVERecord?id=CVE-2021-3506 Référence CVE CVE-2021-3564 https://www.cve.org/CVERecord?id=CVE-2021-3564 Référence CVE CVE-2021-3573 https://www.cve.org/CVERecord?id=CVE-2021-3573 Référence CVE CVE-2021-3612 https://www.cve.org/CVERecord?id=CVE-2021-3612 Référence CVE CVE-2021-3679 https://www.cve.org/CVERecord?id=CVE-2021-3679 Référence CVE CVE-2021-38160 https://www.cve.org/CVERecord?id=CVE-2021-38160 Référence CVE CVE-2021-38198 https://www.cve.org/CVERecord?id=CVE-2021-38198 Référence CVE CVE-2021-38204 https://www.cve.org/CVERecord?id=CVE-2021-38204 Référence CVE CVE-2021-38208 https://www.cve.org/CVERecord?id=CVE-2021-38208 Référence CVE CVE-2021-39648 https://www.cve.org/CVERecord?id=CVE-2021-39648 Référence CVE CVE-2021-39685 https://www.cve.org/CVERecord?id=CVE-2021-39685 Référence CVE CVE-2021-39698 https://www.cve.org/CVERecord?id=CVE-2021-39698 Référence CVE CVE-2021-40490 https://www.cve.org/CVERecord?id=CVE-2021-40490 Référence CVE CVE-2021-4135 https://www.cve.org/CVERecord?id=CVE-2021-4135 Référence CVE CVE-2021-4197 https://www.cve.org/CVERecord?id=CVE-2021-4197 Référence CVE CVE-2021-42008 https://www.cve.org/CVERecord?id=CVE-2021-42008 Référence CVE CVE-2021-43389 https://www.cve.org/CVERecord?id=CVE-

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-653Multiples 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 et une atteinte à la confidentialité des données.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-009145Linux Kernel における NULL ポインタデリファレンスに関する脆弱性

Linux Kernel には、NULL ポインタデリファレンスに関する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
n/a
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 8 Aug 2021 · Last source change 4 Aug 2024, 01:37 UTC · CWE-476 · NULL Pointer Dereference

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-2021-24666
Product sourceUnavailable
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
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-2021-24666↗Public exploit reference↗Patch or update reference↗Patch or update 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-2021-38208 · cve.blacktree.nl