CVE-2021-3716

low-risk
Published 2022-03-02

A flaw was found in nbdkit due to to improperly caching plaintext state across the STARTTLS encryption boundary. A MitM attacker could use this flaw to inject a plaintext NBD_OPT_STRUCTURED_REPLY before proxying everything else a client sends to the server, potentially leading the client to terminate the NBD session. The highest threat from this vulnerability is to system availability.

Do I need to act?

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0.08% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
3
CVSS 3.1/10 Low
NETWORK / HIGH complexity

Affected Products (3)

Nbdkit

Affected Vendors

Redhat Nbdkit Project

References (10)

Issue Tracking https://bugzilla.redhat.com/show_bug.cgi?id=1994695
Patch https://gitlab.com/nbdkit/nbdkit/-/commit/09a13dafb7bb3a38ab52eb5501cba786365ba7...
Patch https://gitlab.com/nbdkit/nbdkit/-/commit/6c5faac6a37077cf2366388a80862bb00616d0...
Broken Link https://listman.redhat.com/archives/libguestfs/2021-August/msg00083.html
Mailing List https://www.openwall.com/lists/oss-security/2021/08/18/2
Issue Tracking https://bugzilla.redhat.com/show_bug.cgi?id=1994695
Patch https://gitlab.com/nbdkit/nbdkit/-/commit/09a13dafb7bb3a38ab52eb5501cba786365ba7...
Patch https://gitlab.com/nbdkit/nbdkit/-/commit/6c5faac6a37077cf2366388a80862bb00616d0...
Broken Link https://listman.redhat.com/archives/libguestfs/2021-August/msg00083.html
Mailing List https://www.openwall.com/lists/oss-security/2021/08/18/2
20
/ 100
low-risk
Severity 11/34 · Low
Exploitability 0/34 · Minimal
Exposure 9/34 · Low