What’s Vulnerable › Vulnerabilities

CVE-2021-38173

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-08-07 · updated 2026-06-17
• Weakness: CWE-77

Description

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.

Affected products

• Debian Linux: 9.0
• digint btrbk: before 0.31.2 — fixed in 0.31.2
• Fedoraproject Fedora: 34, 35

How to fix

Upgrade to a fixed version: digint btrbk 0.31.2. Check the vendor advisory for mitigations.

References

• https://github.com/digint/btrbk/blob/master/ChangeLog
• https://github.com/digint/btrbk/commit/58212de771c381cd4fa05625927080bf264e9584
• https://lists.debian.org/debian-lts-announce/2021/09/msg00002.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BP2T32JMENJFRP2HWXR7FTTZVRTTPECL/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LM7GLTUN5YS4KE2RNBX732EAMVVGNEX3/
• https://github.com/digint/btrbk/blob/master/ChangeLog
• https://github.com/digint/btrbk/commit/58212de771c381cd4fa05625927080bf264e9584
• https://lists.debian.org/debian-lts-announce/2021/09/msg00002.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BP2T32JMENJFRP2HWXR7FTTZVRTTPECL/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LM7GLTUN5YS4KE2RNBX732EAMVVGNEX3/

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