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Vulnerabilities/CVE-2021-28041Public Intelligence Dossier
Source: openbsd · Limited verification•Last verified: •Collection Degraded
CVE-2021-28041Unknown / EvaluatingHIGH (raw)CVSS 7.1CWE-415

ssh-agent in OpenSSH before 8.5 has a double free that may be relevant in a few less-common scenarios, such as unconstrained agent-socket access on a legacy operating system, or the forwarding of an agent to an attacker-controlled host.

Published: 06 Mar 2021•Last updated: 14 Oct 2026, 05:47 PM IST•Source identifier: cve@mitre.org
Dossier completeness: source-provided sections 2 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
7.1HIGH (raw)
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H
Metric sourcenvd@nist.gov
EPSS probability
3.5%0.035
Percentile89th
Weakness type
CWE-415
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

ssh-agent in OpenSSH before 8.5 has a double free that may be relevant in a few less-common scenarios, such as unconstrained agent-socket access on a legacy operating system, or the forwarding of an agent to an attacker-controlled host.

SOC priority

High

Actively exploited

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; HIGH severity; No confirmed exploitation signal in current enrichment

Affected Products & Remediation

9 source-backed products
Affected products and versions (source)
  • openbsd openssh · >= 8.2 < 8.5 · NVD CPE · Source
  • fedoraproject fedora · 33; 34 · NVD CPE · Source
  • netapp cloud backup · version range not provided by source · NVD CPE · Source
  • netapp hci management node · version range not provided by source · NVD CPE · Source
  • netapp solidfire · version range not provided by source · NVD CPE · Source
  • netapp hci compute node firmware · version range not provided by source · NVD CPE · Source
  • netapp hci storage node firmware · version range not provided by source · NVD CPE · Source
  • oracle communications offline mediation controller · 12.0.0.3.0 · NVD CPE · Source
  • oracle zfs storage appliance · 8.8 · NVD CPE · Source
NVD applicability prerequisites: cpe:2.3:h:netapp:hci_compute_node:-:*:*:*:*:*:*:*, cpe:2.3:h:netapp:hci_storage_node:-:*:*:*:*:*:*:*. These are conditions, not proof that an environment is exposed or unaffected.
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched user-interaction-client (CVSS AV:N, CVSS UI:R)

Exposure

  1. Identify endpoints reporting this CVE, especially those used for email and web browsing.Telemetry: DeviceTvmSoftwareVulnerabilities · A network vector that needs user interaction points at user-facing client software. · Rule user-interaction-client

Exploitation evidence

  1. Review unusual child processes started by the affected client application on affected endpoints.Telemetry: DeviceProcessEvents · Hunting hypothesis from the CVSS vector; it does not show that exploitation occurred. · Rule user-interaction-client

Response

  1. Confirm the source-stated update on affected endpoints.Telemetry: DeviceTvmSoftwareVulnerabilities · A follow-up inventory check verifies remediation. · Rule user-interaction-client

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
cve@mitre.org
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*, cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*, cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*, cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*, cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:*, cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:*, cpe:2.3:o:netapp:hci_compute_node_firmware:-:*:*:*:*:*:*:*, cpe:2.3:h:netapp:hci_compute_node:-:*:*:*:*:*:*:*, cpe:2.3:o:netapp:hci_storage_node_firmware:-:*:*:*:*:*:*:*, cpe:2.3:h:netapp:hci_storage_node:-:*:*:*:*:*:*:*

Evidence & Provenance

3 public sources
github.comSource recordnvd.nist.govSource recordlists.fedoraproject.orgSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2021-28041
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2021-28041
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2021-28041"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

Correlated briefings

— No published briefing references this CVE

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.