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Full vulnerability report · 2021
CVE-2021-35477High confidence

n/a — Observable Discrepancy

n/a · n/a

5.5MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

1 package state
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.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
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 record ↗Source updated 9 Sept 2026
Optional official sources

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

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

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-2021-22119

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 actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.

What

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.

Why

The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may obtain information outside the intended access boundary.

What

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.

Why

The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may obtain information outside the intended access boundary.

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 → Observable Discrepancy → obtain information outside the intended access boundary
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-203

CWE-203: Observable Discrepancy. The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.

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: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.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.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-203
A

Official authority intelligence

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

CERT-FR · French · CERTFR-2025-AVI-0088Multiples vulnérabilités dans le noyau Linux de SUSE

de sécurité SUSE SUSE-SU-2025:0268-1 du 28 janvier 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20250268-1 Bulletin de sécurité SUSE SUSE-SU-2025:0269-1 du 28 janvier 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20250269-1 Bulletin de sécurité SUSE SUSE-SU-2025:0289-1 du 29 janvier 2025 https://www.suse.com/support/update/announcement/2025/suse-su-20250289-1 Référence CVE CVE-2020-12770 https://www.cve.org/CVERecord?id=CVE-2020-12770 Référence CVE CVE-2020-36788 https://www.cve.org/CVERecord?id=CVE-2020-36788 Référence CVE CVE-2021-34556 https://www.cve.org/CVERecord?id=CVE-2021-34556 Référence CVE CVE-2021-35477 https://www.cve.org/CVERecord?id=CVE-2021-35477 Référence CVE CVE-2021-38160 https://www.cve.org/CVERecord?id=CVE-2021-38160 Référence CVE CVE-2021-4148 https://www.cve.org/CVERecord?id=CVE-2021-4148 Référence CVE CVE-2021-42327 https://www.cve.org/CVERecord?id=CVE-2021-42327 Référence CVE CVE-2021-46955 https://www.cve.org/CVERecord?id=CVE-2021-46955 Référence CVE CVE-2021-47202 https://www.cve.org/CVERecord?id=CVE-2021-47202 Référence CVE CVE-2021-47291 https://www.cve.org/CVERecord?id=CVE-2021-47291 Référence CVE CVE-2021-47365 https://www.cve.org/CVERecord?id=CVE-2021-47365 Référence CVE CVE-2021-47378 https://www.cve.org/CVERecord?id=CV

Official advisory
CERT-FR · French · CERTFR-2021-AVI-934Multiples vulnérabilités dans le noyau Linux de SUSE

ERecord?id=CVE-2020-27820 Référence CVE CVE-2020-3702 https://www.cve.org/CVERecord?id=CVE-2020-3702 Référence CVE CVE-2021-0941 https://www.cve.org/CVERecord?id=CVE-2021-0941 Référence CVE CVE-2021-20322 https://www.cve.org/CVERecord?id=CVE-2021-20322 Référence CVE CVE-2021-22543 https://www.cve.org/CVERecord?id=CVE-2021-22543 Référence CVE CVE-2021-31916 https://www.cve.org/CVERecord?id=CVE-2021-31916 Référence CVE CVE-2021-34556 https://www.cve.org/CVERecord?id=CVE-2021-34556 Référence CVE CVE-2021-34981 https://www.cve.org/CVERecord?id=CVE-2021-34981 Référence CVE CVE-2021-3542 https://www.cve.org/CVERecord?id=CVE-2021-3542 Référence CVE CVE-2021-35477 https://www.cve.org/CVERecord?id=CVE-2021-35477 Référence CVE CVE-2021-3640 https://www.cve.org/CVERecord?id=CVE-2021-3640 Référence CVE CVE-2021-3653 https://www.cve.org/CVERecord?id=CVE-2021-3653 Référence CVE CVE-2021-3655 https://www.cve.org/CVERecord?id=CVE-2021-3655 Référence CVE CVE-2021-3656 https://www.cve.org/CVERecord?id=CVE-2021-3656 Référence CVE CVE-2021-3659 https://www.cve.org/CVERecord?id=CVE-2021-3659 Référence CVE CVE-2021-3679 https://www.cve.org/CVERecord?id=CVE-2021-3679 Référence CVE CVE-2021-3715 https://www.cve.org/CVERecord?id=CVE-2021-3715 Référence CVE CVE-2021-37159 https://www.cve.org/CVERecord?id=CVE-2021-37159

Official advisory
CERT-FR · French · CERTFR-2021-AVI-923Multiples vulnérabilités dans le noyau Linux de SUSE

ord?id=CVE-2021-20265 Référence CVE CVE-2021-20320 https://www.cve.org/CVERecord?id=CVE-2021-20320 Référence CVE CVE-2021-20322 https://www.cve.org/CVERecord?id=CVE-2021-20322 Référence CVE CVE-2021-22543 https://www.cve.org/CVERecord?id=CVE-2021-22543 Référence CVE CVE-2021-31916 https://www.cve.org/CVERecord?id=CVE-2021-31916 Référence CVE CVE-2021-33033 https://www.cve.org/CVERecord?id=CVE-2021-33033 Référence CVE CVE-2021-34556 https://www.cve.org/CVERecord?id=CVE-2021-34556 Référence CVE CVE-2021-34981 https://www.cve.org/CVERecord?id=CVE-2021-34981 Référence CVE CVE-2021-3542 https://www.cve.org/CVERecord?id=CVE-2021-3542 Référence CVE CVE-2021-35477 https://www.cve.org/CVERecord?id=CVE-2021-35477 Référence CVE CVE-2021-3640 https://www.cve.org/CVERecord?id=CVE-2021-3640 Référence CVE CVE-2021-3653 https://www.cve.org/CVERecord?id=CVE-2021-3653 Référence CVE CVE-2021-3655 https://www.cve.org/CVERecord?id=CVE-2021-3655 Référence CVE CVE-2021-3656 https://www.cve.org/CVERecord?id=CVE-2021-3656 Référence CVE CVE-2021-3659 https://www.cve.org/CVERecord?id=CVE-2021-3659 Référence CVE CVE-2021-3679 https://www.cve.org/CVERecord?id=CVE-2021-3679 Référence CVE CVE-2021-3715 https://www.cve.org/CVERecord?id=CVE-2021-3715 Référence CVE CVE-2021-37159 https://www.cve.org/CVERecord?id=CVE-2021-37159

Official advisory
CERT-FR · French · CERTFR-2021-AVI-916Multiples vulnérabilités dans le noyau Linux de SUSE

ord?id=CVE-2021-20265 Référence CVE CVE-2021-20322 https://www.cve.org/CVERecord?id=CVE-2021-20322 Référence CVE CVE-2021-22543 https://www.cve.org/CVERecord?id=CVE-2021-22543 Référence CVE CVE-2021-31916 https://www.cve.org/CVERecord?id=CVE-2021-31916 Référence CVE CVE-2021-33033 https://www.cve.org/CVERecord?id=CVE-2021-33033 Référence CVE CVE-2021-33909 https://www.cve.org/CVERecord?id=CVE-2021-33909 Référence CVE CVE-2021-34556 https://www.cve.org/CVERecord?id=CVE-2021-34556 Référence CVE CVE-2021-34981 https://www.cve.org/CVERecord?id=CVE-2021-34981 Référence CVE CVE-2021-3542 https://www.cve.org/CVERecord?id=CVE-2021-3542 Référence CVE CVE-2021-35477 https://www.cve.org/CVERecord?id=CVE-2021-35477 Référence CVE CVE-2021-3609 https://www.cve.org/CVERecord?id=CVE-2021-3609 Référence CVE CVE-2021-3640 https://www.cve.org/CVERecord?id=CVE-2021-3640 Référence CVE CVE-2021-3653 https://www.cve.org/CVERecord?id=CVE-2021-3653 Référence CVE CVE-2021-3655 https://www.cve.org/CVERecord?id=CVE-2021-3655 Référence CVE CVE-2021-3656 https://www.cve.org/CVERecord?id=CVE-2021-3656 Référence CVE CVE-2021-3659 https://www.cve.org/CVERecord?id=CVE-2021-3659 Référence CVE CVE-2021-3679 https://www.cve.org/CVERecord?id=CVE-2021-3679 Référence CVE CVE-2021-3715 https://www.cve.org/CVERecord?id=CVE-2021-3715 R

Official advisory
CERT-FR · French · CERTFR-2021-AVI-893Multiples 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 déni de service, une atteinte à l'intégrité des données et une atteinte à la confidentialité des données.

Official advisory
CERT-FR · French · CERTFR-2021-AVI-886Multiples 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 une atteinte à l'intégrité des données.

Official advisory
CERT-FR · French · CERTFR-2021-AVI-868Multiples 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
CERT-FR · French · CERTFR-2021-AVI-855Multiples 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
CERT-FR · French · CERTFR-2021-AVI-814Multiples vulnérabilités dans le noyau Linux d'Ubuntu

De multiples vulnérabilités ont été découvertes dans le noyau Linux d'Ubuntu. Certaines d'entre elles permettent à un attaquant de provoquer une exécution de code arbitraire, un déni de service à distance et un contournement de la politique de sécurité.

Official advisory
CERT-FR · French · CERTFR-2021-AVI-785Multiples vulnérabilités dans le noyau Linux de SUSE

/support/update/announcement/2021/suse-su-20213389-1/ Bulletin de sécurité SUSE suse-su-20213401-1 du 13 octobre 2021 https://www.suse.com/support/update/announcement/2021/suse-su-20213401-1/ Bulletin de sécurité SUSE suse-su-20213415-1 du 14 octobre 2021 https://www.suse.com/support/update/announcement/2021/suse-su-20213415-1/ Référence CVE CVE-2020-12770 https://www.cve.org/CVERecord?id=CVE-2020-12770 Référence CVE CVE-2020-3702 https://www.cve.org/CVERecord?id=CVE-2020-3702 Référence CVE CVE-2021-31440 https://www.cve.org/CVERecord?id=CVE-2021-31440 Référence CVE CVE-2021-34556 https://www.cve.org/CVERecord?id=CVE-2021-34556 Référence CVE CVE-2021-35477 https://www.cve.org/CVERecord?id=CVE-2021-35477 Référence CVE CVE-2021-3573 https://www.cve.org/CVERecord?id=CVE-2021-3573 Référence CVE CVE-2021-3640 https://www.cve.org/CVERecord?id=CVE-2021-3640 Référence CVE CVE-2021-3653 https://www.cve.org/CVERecord?id=CVE-2021-3653 Référence CVE CVE-2021-3656 https://www.cve.org/CVERecord?id=CVE-2021-3656 Référence CVE CVE-2021-3669 https://www.cve.org/CVERecord?id=CVE-2021-3669 Référence CVE CVE-2021-3679 https://www.cve.org/CVERecord?id=CVE-2021-3679 Référence CVE CVE-2021-3715 https://www.cve.org/CVERecord?id=CVE-2021-3715 Référence CVE CVE-2021-3732 https://www.cve.org/CVERecord?id=CVE-2021-3732 R

Official advisory
CERT-FR · French · CERTFR-2021-AVI-742Multiples vulnérabilités dans le noyau Linux d'Ubuntu

De multiples vulnérabilités ont été découvertes dans le noyau Linux d'Ubuntu. Certaines d'entre 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-2021-AVI-730Multiples vulnérabilités dans le noyau Linux de SUSE

SE suse-su-20213206-1 du 23 septembre 2021 https://www.suse.com/support/update/announcement/2021/suse-su-20213206-1/ Bulletin de sécurité SUSE suse-su-20213217-1 du 23 septembre 2021 https://www.suse.com/support/update/announcement/2021/suse-su-20213217-1/ Référence CVE CVE-2018-9517 https://www.cve.org/CVERecord?id=CVE-2018-9517 Référence CVE CVE-2019-3874 https://www.cve.org/CVERecord?id=CVE-2019-3874 Référence CVE CVE-2019-3900 https://www.cve.org/CVERecord?id=CVE-2019-3900 Référence CVE CVE-2020-12770 https://www.cve.org/CVERecord?id=CVE-2020-12770 Référence CVE CVE-2021-34556 https://www.cve.org/CVERecord?id=CVE-2021-34556 Référence CVE CVE-2021-35477 https://www.cve.org/CVERecord?id=CVE-2021-35477 Référence CVE CVE-2021-3640 https://www.cve.org/CVERecord?id=CVE-2021-3640 Référence CVE CVE-2021-3653 https://www.cve.org/CVERecord?id=CVE-2021-3653 Référence CVE CVE-2021-3656 https://www.cve.org/CVERecord?id=CVE-2021-3656 Référence CVE CVE-2021-3679 https://www.cve.org/CVERecord?id=CVE-2021-3679 Référence CVE CVE-2021-3732 https://www.cve.org/CVERecord?id=CVE-2021-3732 Référence CVE CVE-2021-3739 https://www.cve.org/CVERecord?id=CVE-2021-3739 Référence CVE CVE-2021-3743 https://www.cve.org/CVERecord?id=CVE-2021-3743 Référence CVE CVE-2021-3753 https://www.cve.org/CVERecord?id=CVE-2021-3753 R

Official advisory
CERT-FR · French · CERTFR-2021-AVI-727Multiples vulnérabilités dans le noyau Linux de SUSE

SE suse-su-20213179-1 du 21 septembre 2021 https://www.suse.com/support/update/announcement/2021/suse-su-20213179-1/ Bulletin de sécurité SUSE suse-su-20213192-1 du 22 septembre 2021 https://www.suse.com/support/update/announcement/2021/suse-su-20213192-1/ Référence CVE CVE-2018-9517 https://www.cve.org/CVERecord?id=CVE-2018-9517 Référence CVE CVE-2019-3874 https://www.cve.org/CVERecord?id=CVE-2019-3874 Référence CVE CVE-2019-3900 https://www.cve.org/CVERecord?id=CVE-2019-3900 Référence CVE CVE-2020-12770 https://www.cve.org/CVERecord?id=CVE-2020-12770 Référence CVE CVE-2021-34556 https://www.cve.org/CVERecord?id=CVE-2021-34556 Référence CVE CVE-2021-35477 https://www.cve.org/CVERecord?id=CVE-2021-35477 Référence CVE CVE-2021-3640 https://www.cve.org/CVERecord?id=CVE-2021-3640 Référence CVE CVE-2021-3653 https://www.cve.org/CVERecord?id=CVE-2021-3653 Référence CVE CVE-2021-3656 https://www.cve.org/CVERecord?id=CVE-2021-3656 Référence CVE CVE-2021-3679 https://www.cve.org/CVERecord?id=CVE-2021-3679 Référence CVE CVE-2021-3732 https://www.cve.org/CVERecord?id=CVE-2021-3732 Référence CVE CVE-2021-3739 https://www.cve.org/CVERecord?id=CVE-2021-3739 Référence CVE CVE-2021-3743 https://www.cve.org/CVERecord?id=CVE-2021-3743 Référence CVE CVE-2021-3753 https://www.cve.org/CVERecord?id=CVE-2021-3753 R

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.
Patch available
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
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 2 Aug 2021 · Last source change 4 Aug 2024, 00:40 UTC · CWE-203 · Observable Discrepancy

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-2021-22119
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

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
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-2021-35477 · cve.blacktree.nl