CVE-2021-3716

Description

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.

Category

3.1
CVSS
Severity: Low
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.08%
Third-Party Advisory redhat.com Third-Party Advisory gitlab.com Third-Party Advisory gitlab.com Third-Party Advisory openwall.com
Affected: n/a nbdkit
Published at:
Updated at:

References

Link Tags
https://www.openwall.com/lists/oss-security/2021/08/18/2 third party advisory mailing list
https://listman.redhat.com/archives/libguestfs/2021-August/msg00083.html broken link
https://gitlab.com/nbdkit/nbdkit/-/commit/09a13dafb7bb3a38ab52eb5501cba786365ba7fd third party advisory patch
https://gitlab.com/nbdkit/nbdkit/-/commit/6c5faac6a37077cf2366388a80862bb00616d0d8 third party advisory patch
https://bugzilla.redhat.com/show_bug.cgi?id=1994695 issue tracking third party advisory patch

Frequently Asked Questions

What is the severity of CVE-2021-3716?
CVE-2021-3716 has been scored as a low severity vulnerability.
How to fix CVE-2021-3716?
To fix CVE-2021-3716, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-3716 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-3716 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-3716?
CVE-2021-3716 affects n/a nbdkit.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.