CVE-2021-40120

MEDIUMNVD 6.57.2▲
EchelonGraph scoreMEDIUM confidence

Score 7.2 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 6.5; sources differ by 0.7.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 2%CVSS: 6.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

A vulnerability in the web-based management interface of certain Cisco Small Business RV Series Routers could allow an authenticated, remote attacker with administrative privileges to inject arbitrary commands into the underlying operating system and execute them using root-level privileges. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending malicious input to a specific field in the web-based management interface of an affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying Linux operating system as a user with root-level privileges.

CVSS v3
6.5
EG Score
7.2(medium)
EPSS
77.8%
KEV
Not listed

Published

November 4, 2021

Last Modified

November 21, 2024

References (2)

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 47× 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 101 total refreshes for this CVE.

  1. 2026-07-21 15:22 UTCEPSS rescore
  2. 2026-07-21 15:22 UTCEPSS rescore
  3. 2026-07-20 17:05 UTCEPSS rescore
  4. 2026-07-19 14:29 UTCEPSS rescore
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  1. 2026-07-06 02:21 UTCEPSS rescore
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  6. 2026-07-02 16:57 UTCEPSS rescore
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  8. 2026-06-30 23:20 UTCEPSS rescore
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  20. 2026-06-23 21:31 UTCEPSS rescore
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  22. 2026-06-22 14:24 UTCEPSS rescore
  23. 2026-06-21 14:55 UTCEPSS rescore
  24. 2026-06-21 01:58 UTCEPSS rescore
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  26. 2026-06-19 19:24 UTCEPSS rescore
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  28. 2026-06-18 17:51 UTCEPSS rescore
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  40. 2026-06-12 23:10 UTCEPSS rescore
  41. 2026-06-11 13:58 UTCEPSS rescore
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  43. 2026-06-10 22:16 UTCEPSS rescore
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  45. 2026-06-10 13:20 UTCEPSS rescore
  46. 2026-06-08 14:15 UTCEPSS rescore
  47. 2026-06-08 14:15 UTCEPSS rescore
  48. 2026-06-07 15:23 UTCEPSS rescore
  49. 2026-06-07 15:23 UTCEPSS rescore
  50. 2026-06-06 13:46 UTCEPSS rescore
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  52. 2026-06-05 22:45 UTCEPSS rescore
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  63. 2026-05-31 00:15 UTCEPSS rescore
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  65. 2026-05-29 13:42 UTCEPSS rescore
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  68. 2026-05-27 13:39 UTCEPSS rescore
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  70. 2026-05-26 13:42 UTCEPSS rescore
  71. 2026-05-26 13:42 UTCEPSS rescore
  72. 2026-05-26 08:02 UTCEG score recompute
  73. 2026-05-26 08:02 UTCGHSA enrichment
  74. 2026-05-26 07:17 UTCEPSS rescore
  75. 2026-05-26 07:17 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-40120?
CVE-2021-40120 is a medium vulnerability published on November 4, 2021. A vulnerability in the web-based management interface of certain Cisco Small Business RV Series Routers could allow an authenticated, remote attacker with administrative privileges to inject arbitrary commands into the underlying operating system and execute them using root-level privileges. This…
When was CVE-2021-40120 disclosed?
CVE-2021-40120 was first published in the National Vulnerability Database on November 4, 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-2021-40120 actively exploited?
CVE-2021-40120 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 77.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-40120?
CVE-2021-40120 has a CVSS v3 base score of 6.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 7.2.
How do I remediate CVE-2021-40120?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-40120, 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.

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