CVE-2021-3716

LOWNVD 3.13.1—
EchelonGraph scoreMEDIUM confidence

Score 3.1 from GitHub Security Advisory (severity: LOW) published 2022-03-04. NVD baseline CVSS 3.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
3.1
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 3.1Exploit: NoneExposed: 0

A fix is available — apply it.

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.

CVSS v3
3.1
EG Score
3.1(medium)
EPSS
43.6%
KEV
Not listed

Published

March 2, 2022

Last Modified

November 21, 2024

References (10)

Vendor Advisories for CVE-2021-3716(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatvirt:rhel-8060020220408104655.d63f516d2022-05-10redhat
redhatvirt-devel:av-8050020220115095224.c53685002022-02-02redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 12× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 105 total refreshes for this CVE.

  1. 2026-07-21 15:22 UTCEPSS rescore
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  1. 2026-07-06 02:21 UTCEPSS rescore
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  9. 2026-06-30 23:20 UTCEPSS rescore
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  11. 2026-06-29 19:23 UTCOSV refresh
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  43. 2026-06-12 08:06 UTCOSV refresh
  44. 2026-06-11 13:58 UTCEPSS rescore
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  46. 2026-06-10 22:16 UTCEPSS rescore
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  75. 2026-05-26 07:17 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-3716?
CVE-2021-3716 is a low vulnerability published on March 2, 2022. 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 NBDOPTSTRUCTURED_REPLY before proxying everything else a client sends to the server, potentially leading the client to terminate…
When was CVE-2021-3716 disclosed?
CVE-2021-3716 was first published in the National Vulnerability Database on March 2, 2022, 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-2021-3716 actively exploited?
CVE-2021-3716 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 43.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-3716?
CVE-2021-3716 has a CVSS v3 base score of 3.1 (NVD).
How do I remediate CVE-2021-3716?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3716, 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

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