CVE-2020-3561

MEDIUMNVD 4.74.7—
EchelonGraph scoreMEDIUM confidence

Score 4.7 from GitHub Security Advisory published 2022-05-24. NVD baseline CVSS 4.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, nvd
4.7
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 4.7Exploit: NoneExposed: 0

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

A vulnerability in the Clientless SSL VPN (WebVPN) of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to inject arbitrary HTTP headers in the responses of the affected system. The vulnerability is due to improper input sanitization. An attacker could exploit this vulnerability by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to conduct a CRLF injection attack, adding arbitrary HTTP headers in the responses of the system and redirecting the user to arbitrary websites.

CVSS v3
4.7
EG Score
4.7(medium)
EPSS
67.0%
KEV
Not listed

Published

October 21, 2020

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 10× in last 7d / 41× 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.

  1. 2026-07-22 14:05 UTCEPSS rescore
  2. 2026-07-21 15:22 UTCEPSS rescore
  3. 2026-07-21 15:22 UTCEPSS rescore
  4. 2026-07-20 17:04 UTCEPSS rescore
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  6. 2026-07-19 14:28 UTCEPSS rescore
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  8. 2026-07-19 02:26 UTCEPSS rescore
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  10. 2026-07-16 16:59 UTCEPSS rescore
  11. 2026-07-15 16:55 UTCEPSS rescore
  12. 2026-07-15 16:55 UTCEPSS rescore
  13. 2026-07-15 01:57 UTCEPSS rescore
  14. 2026-07-13 22:27 UTCEPSS rescore
  15. 2026-07-13 22:27 UTCEPSS rescore
  16. 2026-07-13 06:10 UTCEPSS rescore
  17. 2026-07-13 06:10 UTCEPSS rescore
  18. 2026-07-12 05:44 UTCEPSS rescore
  19. 2026-07-11 08:25 UTCEPSS rescore
  20. 2026-07-11 08:25 UTCEPSS rescore
  21. 2026-07-09 19:07 UTCEPSS rescore
  22. 2026-07-08 15:12 UTCEPSS rescore
  23. 2026-07-07 13:43 UTCEPSS rescore
  24. 2026-07-06 16:25 UTCEPSS rescore
  25. 2026-07-06 16:25 UTCEPSS rescore
Show 64 more
  1. 2026-07-06 02:21 UTCEPSS rescore
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  3. 2026-07-04 06:29 UTCEPSS rescore
  4. 2026-07-04 06:29 UTCEPSS rescore
  5. 2026-06-30 23:20 UTCEPSS rescore
  6. 2026-06-30 23:20 UTCEPSS rescore
  7. 2026-06-29 14:04 UTCEPSS rescore
  8. 2026-06-28 04:54 UTCEPSS rescore
  9. 2026-06-28 04:54 UTCEPSS rescore
  10. 2026-06-27 03:06 UTCEPSS rescore
  11. 2026-06-27 03:06 UTCEPSS rescore
  12. 2026-06-25 13:48 UTCEPSS rescore
  13. 2026-06-24 14:03 UTCEPSS rescore
  14. 2026-06-24 14:03 UTCEPSS rescore
  15. 2026-06-23 21:31 UTCEPSS rescore
  16. 2026-06-23 21:31 UTCEPSS rescore
  17. 2026-06-22 14:23 UTCEPSS rescore
  18. 2026-06-22 14:23 UTCEPSS rescore
  19. 2026-06-21 14:54 UTCEPSS rescore
  20. 2026-06-21 14:54 UTCEPSS rescore
  21. 2026-06-21 01:57 UTCEPSS rescore
  22. 2026-06-19 19:24 UTCEPSS rescore
  23. 2026-06-19 19:23 UTCEPSS rescore
  24. 2026-06-18 17:50 UTCEPSS rescore
  25. 2026-06-18 17:50 UTCEPSS rescore
  26. 2026-06-17 17:50 UTCEPSS rescore
  27. 2026-06-16 17:50 UTCEPSS rescore
  28. 2026-06-15 17:46 UTCEPSS rescore
  29. 2026-06-14 23:15 UTCEPSS rescore
  30. 2026-06-13 22:58 UTCEPSS rescore
  31. 2026-06-12 23:10 UTCEPSS rescore
  32. 2026-06-11 13:58 UTCEPSS rescore
  33. 2026-06-10 22:16 UTCEPSS rescore
  34. 2026-06-10 13:20 UTCEPSS rescore
  35. 2026-06-08 14:15 UTCEPSS rescore
  36. 2026-06-07 15:23 UTCEPSS rescore
  37. 2026-06-07 15:23 UTCEPSS rescore
  38. 2026-06-07 15:23 UTCEPSS rescore
  39. 2026-06-06 13:46 UTCEPSS rescore
  40. 2026-06-06 13:45 UTCEPSS rescore
  41. 2026-06-05 22:45 UTCEPSS rescore
  42. 2026-06-05 22:45 UTCEPSS rescore
  43. 2026-06-05 06:08 UTCEPSS rescore
  44. 2026-06-05 06:08 UTCEPSS rescore
  45. 2026-06-04 13:10 UTCEPSS rescore
  46. 2026-06-04 13:10 UTCEPSS rescore
  47. 2026-06-02 20:11 UTCEPSS rescore
  48. 2026-06-02 20:11 UTCEPSS rescore
  49. 2026-06-01 13:50 UTCEPSS rescore
  50. 2026-05-31 22:29 UTCEPSS rescore
  51. 2026-05-31 22:29 UTCEPSS rescore
  52. 2026-05-31 00:15 UTCEPSS rescore
  53. 2026-05-31 00:15 UTCEPSS rescore
  54. 2026-05-29 13:42 UTCEPSS rescore
  55. 2026-05-28 13:43 UTCEPSS rescore
  56. 2026-05-28 13:43 UTCEPSS rescore
  57. 2026-05-27 13:39 UTCEPSS rescore
  58. 2026-05-27 13:39 UTCEPSS rescore
  59. 2026-05-26 13:42 UTCEPSS rescore
  60. 2026-05-26 13:42 UTCEPSS rescore
  61. 2026-05-26 07:17 UTCEPSS rescore
  62. 2026-05-26 07:17 UTCEPSS rescore
  63. 2026-05-23 06:14 UTCEG score recompute
  64. 2026-05-23 06:14 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2020-3561?
CVE-2020-3561 is a medium vulnerability published on October 21, 2020. A vulnerability in the Clientless SSL VPN (WebVPN) of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to inject arbitrary HTTP headers in the responses of the affected system. The vulnerability is due…
When was CVE-2020-3561 disclosed?
CVE-2020-3561 was first published in the National Vulnerability Database on October 21, 2020, 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-2020-3561 actively exploited?
CVE-2020-3561 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 67.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-3561?
CVE-2020-3561 has a CVSS v3 base score of 4.7 (NVD).
How do I remediate CVE-2020-3561?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-3561, 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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