CVE-2021-38173

CRITICALNVD 9.89.8—

9.8

Btrbk before 0.31.2 allows command execution because of the mishandling of remote hosts filtering SSH commands using ssh_filter_btrbk.sh in authorized_keys.

CVSS v3: 9.8
EG Score: 9.8(medium)
EPSS: 41.8%
KEV: Not listed

Published

August 7, 2021

Last Modified

November 21, 2024

Advisory Details (5)

Auto-updated May 26, 2026

Patch available. Sources: github_commit.

generic

[SECURITY] Fedora 34 Update: btrbk-0.31.3-1.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LM7GLTUN5YS4KE2RNBX732EAMVVGNEX3/

generic

[SECURITY] Fedora 35 Update: btrbk-0.31.3-1.fc35 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BP2T32JMENJFRP2HWXR7FTTZVRTTPECL/

generic Patch Available

[SECURITY] [DLA 2755-1] btrbk security update

https://lists.debian.org/debian-lts-announce/2021/09/msg00002.html

github_commit

commit 58212de771c3 (digint/btrbk)

Fix landed in digint/btrbk commit 58212de771c3 — awaiting tagged release

https://github.com/digint/btrbk/commit/58212de771c381cd4fa05625927080bf264e9584

generic

btrbk/ChangeLog at master · digint/btrbk · GitHub

https://github.com/digint/btrbk/blob/master/ChangeLog

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-77Command Injection

Data Freshness Timeline

(refreshed 12× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-04 13:10 UTCepss_batch
2026-06-04 13:10 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 12:29 UTCEG score recompute
2026-05-26 12:29 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2021-38173?

CVE-2021-38173 is a critical vulnerability published on August 7, 2021. Btrbk before 0.31.2 allows command execution because of the mishandling of remote hosts filtering SSH commands using sshfilterbtrbk.sh in authorized_keys.

When was CVE-2021-38173 disclosed?

CVE-2021-38173 was first published in the National Vulnerability Database on August 7, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-38173 actively exploited?

CVE-2021-38173 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 41.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-38173?

CVE-2021-38173 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2021-38173?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-38173, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-38173

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CVE-2021-38173

📅 Published

🔄 Last Modified

📋 Advisory Details (5)

[SECURITY] Fedora 34 Update: btrbk-0.31.3-1.fc34 - package-announce - Fedora mailing-lists

[SECURITY] Fedora 35 Update: btrbk-0.31.3-1.fc35 - package-announce - Fedora mailing-lists

[SECURITY] [DLA 2755-1] btrbk security update

commit 58212de771c3 (digint/btrbk)

btrbk/ChangeLog at master · digint/btrbk · GitHub

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-38173?

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Published

Last Modified

Advisory Details (5)

Frequently asked(5)

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