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Full vulnerability report · 2021
CVE-2020-27835High confidence

A local user could use this flaw to crash the system

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 4 Aug 2024

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 0.31% 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.5.9.15-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.9.15-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.9.15-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourcelinuxVendor fix publishedDebian records a fixed source-package version for this release.5.9.15-1Debian Security Tracker ↗Source updated 5 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-2020-27835 · CSAF 2.0 · revision 48 · interimSUSE Product Security TeamCVE-2020-27835
33 known affected

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

  • kernel-source-azure as component of HPE Helion OpenStack 8
  • kernel-source-azure as component of SUSE Enterprise Storage 6
  • kernel-source-azure as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • kernel-source-azure as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • kernel-source-azure as component of SUSE Linux Enterprise High Performance Computing 15
  • kernel-source-azure as component of SUSE Linux Enterprise Module for Public Cloud 15 SP1
  • kernel-source-azure as component of SUSE Linux Enterprise Module for Public Cloud 15
  • kernel-source-azure as component of SUSE Linux Enterprise Server 12 SP4-ESPOS
  • kernel-source-azure as component of SUSE Linux Enterprise Server 12 SP4-LTSS
  • kernel-source-azure as component of SUSE Linux Enterprise Server 12 SP4
  • kernel-source-azure as component of SUSE Linux Enterprise Server 15 SP1
  • kernel-source-azure as component of SUSE Linux Enterprise Server 15
Summary
A use after free in the Linux kernel infiniband hfi1 driver in versions prior to 5.10-rc6 was found in the way user calls Ioctl after open dev file and fork. A local user could use this flaw to crash the system.
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-2020-20334

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 use after free in the Linux kernel infiniband hfi1 driver in versions prior to 5.10-rc6 was found in the way user calls Ioctl after open dev file and fork. A local user could use this flaw to crash the system.

What

A use after free in the Linux kernel infiniband hfi1 driver in versions prior to 5.10-rc6 was found in the way user calls Ioctl after open dev file and fork. A local user could use this flaw to crash the system.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

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

What

A use after free in the Linux kernel infiniband hfi1 driver in versions prior to 5.10-rc6 was found in the way user calls Ioctl after open dev file and fork. A local user could use this flaw to crash the system.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation with elevated 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.
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 → Use After Free → disrupt the affected service
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-416 ↗

CWE-416: Use After Free. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

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: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.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.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-416
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-20210113Security Bulletin 13 Jan 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 13 Jan 2021, published on 13 January 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0336Multiples vulnérabilités dans le noyau Linux de SUSE

se-su-20251263-1 Bulletin de sécurité SUSE SUSE-SU-2025:1275-1 du 15 avril 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20251275-1 Bulletin de sécurité SUSE SUSE-SU-2025:1276-1 du 15 avril 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20251276-1 Bulletin de sécurité SUSE SUSE-SU-2025:1278-1 du 15 avril 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20251278-1 Bulletin de sécurité SUSE SUSE-SU-2025:1293-1 du 16 avril 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20251293-1 Référence CVE CVE-2017-5753 https://www.cve.org/CVERecord?id=CVE-2017-5753 Référence CVE CVE-2020-27835 https://www.cve.org/CVERecord?id=CVE-2020-27835 Référence CVE CVE-2021-4453 https://www.cve.org/CVERecord?id=CVE-2021-4453 Référence CVE CVE-2021-4454 https://www.cve.org/CVERecord?id=CVE-2021-4454 Référence CVE CVE-2021-46925 https://www.cve.org/CVERecord?id=CVE-2021-46925 Référence CVE CVE-2021-47248 https://www.cve.org/CVERecord?id=CVE-2021-47248 Référence CVE CVE-2021-47517 https://www.cve.org/CVERecord?id=CVE-2021-47517 Référence CVE CVE-2021-47631 https://www.cve.org/CVERecord?id=CVE-2021-47631 Référence CVE CVE-2021-47632 https://www.cve.org/CVERecord?id=CVE-2021-47632 Référence CVE CVE-2021-47633 https://www.cve.org/CVERecord?id=CVE-

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0307Multiples vulnérabilités dans le noyau Linux de SUSE

se-su-20251178-1 Bulletin de sécurité SUSE SUSE-SU-2025:1180-1 du 09 avril 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20251180-1 Bulletin de sécurité SUSE SUSE-SU-2025:1183-1 du 09 avril 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20251183-1 Bulletin de sécurité SUSE SUSE-SU-2025:1194-1 du 10 avril 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20251194-1 Bulletin de sécurité SUSE SUSE-SU-2025:1195-1 du 10 avril 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20251195-1 Référence CVE CVE-2017-5753 https://www.cve.org/CVERecord?id=CVE-2017-5753 Référence CVE CVE-2020-27835 https://www.cve.org/CVERecord?id=CVE-2020-27835 Référence CVE CVE-2021-4453 https://www.cve.org/CVERecord?id=CVE-2021-4453 Référence CVE CVE-2021-4454 https://www.cve.org/CVERecord?id=CVE-2021-4454 Référence CVE CVE-2021-47248 https://www.cve.org/CVERecord?id=CVE-2021-47248 Référence CVE CVE-2021-47517 https://www.cve.org/CVERecord?id=CVE-2021-47517 Référence CVE CVE-2021-47631 https://www.cve.org/CVERecord?id=CVE-2021-47631 Référence CVE CVE-2021-47632 https://www.cve.org/CVERecord?id=CVE-2021-47632 Référence CVE CVE-2021-47633 https://www.cve.org/CVERecord?id=CVE-2021-47633 Référence CVE CVE-2021-47635 https://www.cve.org/CVERecord?id=CVE-

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-149Multiples vulnérabilités dans le noyau Linux d'Ubuntu

d?id=CVE-2020-25668 Référence CVE CVE-2020-25669 https://www.cve.org/CVERecord?id=CVE-2020-25669 Référence CVE CVE-2020-25704 https://www.cve.org/CVERecord?id=CVE-2020-25704 Référence CVE CVE-2020-27152 https://www.cve.org/CVERecord?id=CVE-2020-27152 Référence CVE CVE-2020-27673 https://www.cve.org/CVERecord?id=CVE-2020-27673 Référence CVE CVE-2020-27675 https://www.cve.org/CVERecord?id=CVE-2020-27675 Référence CVE CVE-2020-27777 https://www.cve.org/CVERecord?id=CVE-2020-27777 Référence CVE CVE-2020-27815 https://www.cve.org/CVERecord?id=CVE-2020-27815 Référence CVE CVE-2020-27830 https://www.cve.org/CVERecord?id=CVE-2020-27830 Référence CVE CVE-2020-27835 https://www.cve.org/CVERecord?id=CVE-2020-27835 Référence CVE CVE-2020-28374 https://www.cve.org/CVERecord?id=CVE-2020-28374 Référence CVE CVE-2020-28588 https://www.cve.org/CVERecord?id=CVE-2020-28588 Référence CVE CVE-2020-28915 https://www.cve.org/CVERecord?id=CVE-2020-28915 Référence CVE CVE-2020-28941 https://www.cve.org/CVERecord?id=CVE-2020-28941 Référence CVE CVE-2020-28974 https://www.cve.org/CVERecord?id=CVE-2020-28974 Référence CVE CVE-2020-29368 https://www.cve.org/CVERecord?id=CVE-2020-29368 Référence CVE CVE-2020-29369 https://www.cve.org/CVERecord?id=CVE-2020-29369 Référence CVE CVE-2020-29371 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-138Multiples 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, une exécution de code arbitraire et un déni de service.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-120Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2020-25285 Référence CVE CVE-2020-25639 https://www.cve.org/CVERecord?id=CVE-2020-25639 Référence CVE CVE-2020-25668 https://www.cve.org/CVERecord?id=CVE-2020-25668 Référence CVE CVE-2020-25669 https://www.cve.org/CVERecord?id=CVE-2020-25669 Référence CVE CVE-2020-27068 https://www.cve.org/CVERecord?id=CVE-2020-27068 Référence CVE CVE-2020-27673 https://www.cve.org/CVERecord?id=CVE-2020-27673 Référence CVE CVE-2020-27777 https://www.cve.org/CVERecord?id=CVE-2020-27777 Référence CVE CVE-2020-27786 https://www.cve.org/CVERecord?id=CVE-2020-27786 Référence CVE CVE-2020-27825 https://www.cve.org/CVERecord?id=CVE-2020-27825 Référence CVE CVE-2020-27835 https://www.cve.org/CVERecord?id=CVE-2020-27835 Référence CVE CVE-2020-28374 https://www.cve.org/CVERecord?id=CVE-2020-28374 Référence CVE CVE-2020-28915 https://www.cve.org/CVERecord?id=CVE-2020-28915 Référence CVE CVE-2020-28974 https://www.cve.org/CVERecord?id=CVE-2020-28974 Référence CVE CVE-2020-29371 https://www.cve.org/CVERecord?id=CVE-2020-29371 Référence CVE CVE-2020-29568 https://www.cve.org/CVERecord?id=CVE-2020-29568 Référence CVE CVE-2020-29569 https://www.cve.org/CVERecord?id=CVE-2020-29569 Référence CVE CVE-2020-29660 https://www.cve.org/CVERecord?id=CVE-2020-29660 Référence CVE CVE-2020-29661 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-111Multiples 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 une exécution de code arbitraire à distance, un déni de service et une atteinte à l'intégrité des données.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2020-015312Linux kernel における解放済みメモリの使用に関する脆弱性

Linux kernel には、解放済みメモリの使用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
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 7 Jan 2021 · Last source change 4 Aug 2024, 16:25 UTC · CWE-416 · Use After Free

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-2020-20334
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-2020-20334↗Vendor CSAF · SUSE Product Security Team↗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-2020-27835 · cve.blacktree.nl