CVE-2022-20737

HIGHNVD 8.58.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This high-severity CVE scores 8.5 under NVD CVSS v3. EPSS exploit probability: 1.2% (67th percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 7.1 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2022-05-04) is not newer than that change (2024-11-21), so it does not.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this week
8.5EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.2%CVSS: 8.5Exploit: None knownExposed services: Not assessed

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

A vulnerability in the handler for HTTP authentication for resources accessed through the Clientless SSL VPN portal of Cisco Adaptive Security Appliance (ASA) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device or to obtain portions of process memory from an affected device. This vulnerability is due to insufficient bounds checking when parsing specific HTTP authentication messages. An attacker could exploit this vulnerability by sending malicious traffic to an affected device acting as a VPN Gateway. To send this malicious traffic, an attacker would need to control a web server that can be accessed through the Clientless SSL VPN portal. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition, or to retrieve bytes from the device process memory that may contain sensitive information.

CVSS v3
8.5
EG Score
8.5HIGHmedium confidence
EG Risk
39
EG Risk 39/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity85% × 45%
Impact severity (EG Severity): CVSS 8.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
1.2%
EPSS %ILE
67th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (8.5): severity, escalated by confirmed exploitation. This CVE's 8.5 is its impact severity (EG Severity), not escalated.

EG Severity
8.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
1.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-20). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

May 3, 2022

Last Modified

November 21, 2024

Advisory Details (1)

Auto-updated Sep 2, 2026
No fix on record yet.
Web page

Cisco Adaptive Security Appliance Software Clientless SSL VPN Heap Overflow Vulnerability

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ssl-vpn-heap-zLX3FdX

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 34× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 95 of 186 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 5 repeat rows among the latest 100 are merged into the row they repeat. The 91 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-23 16:28 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  2. 2026-10-22 16:29 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  3. 2026-10-21 16:28 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  4. 2026-10-21 08:09 UTCEG score recompute
  5. 2026-10-21 08:09 UTCGHSA enrichmentGHSA-m263-3fx7-gm9v · GitHub severity HIGH · GitHub CVSS 7.1
  6. 2026-10-20 16:28 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  7. 2026-10-19 16:28 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  8. 2026-10-18 16:28 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  9. 2026-10-18 08:45 UTCEG score recompute
  10. 2026-10-17 16:29 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  11. 2026-10-16 16:34 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  12. 2026-10-15 16:28 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  13. 2026-10-14 16:29 UTCEPSS rescoreEPSS 1.2% · 67th percentile
  14. 2026-10-13 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  15. 2026-10-12 19:02 UTCEG score recompute
  16. 2026-10-12 16:30 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  17. 2026-10-11 23:28 UTCEG score recompute
  18. 2026-10-11 13:44 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  19. 2026-10-10 19:56 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  20. 2026-10-09 20:04 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  21. 2026-10-08 16:40 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  22. 2026-10-07 23:45 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  23. 2026-10-06 15:14 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  24. 2026-10-05 17:40 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  25. 2026-10-04 23:19 UTCEPSS rescoreEPSS 1.2% · 66th percentile
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  1. 2026-10-03 14:22 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  2. 2026-10-02 16:23 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  3. 2026-09-30 15:48 UTCEG score recompute
  4. 2026-09-30 15:00 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  5. 2026-09-29 15:15 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  6. 2026-09-28 13:47 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  7. 2026-09-26 15:54 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  8. 2026-09-26 00:21 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  9. 2026-09-24 14:00 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  10. 2026-09-23 13:45 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  11. 2026-09-22 14:44 UTCEPSS rescoreEPSS 1.2% · 66th percentile
  12. 2026-09-21 20:28 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  13. 2026-09-20 20:13 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  14. 2026-09-19 15:38 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  15. 2026-09-18 19:24 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  16. 2026-09-17 19:23 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  17. 2026-09-16 14:05 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  18. 2026-09-15 03:06 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  19. 2026-09-12 14:57 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  20. 2026-09-11 14:49 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  21. 2026-09-11 09:33 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  22. 2026-09-08 21:57 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  23. 2026-09-07 15:58 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  24. 2026-09-06 13:45 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  25. 2026-09-05 15:25 UTCEPSS rescoreEPSS 1.2% · 64th percentile
  26. 2026-09-04 13:57 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  27. 2026-09-04 05:03 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  28. 2026-09-02 14:09 UTCEPSS rescoreEPSS 1.2% · 65th percentile
  29. 2026-09-01 13:51 UTCEPSS rescoreEPSS 1.2% · 64th percentile
  30. 2026-08-30 19:14 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  31. 2026-08-30 01:19 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  32. 2026-08-28 21:38 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  33. 2026-08-27 14:22 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  34. 2026-08-26 14:43 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  35. 2026-08-25 13:46 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  36. 2026-08-24 14:13 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  37. 2026-08-21 23:46 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  38. 2026-08-20 22:52 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  39. 2026-08-19 17:01 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  40. 2026-08-18 13:45 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  41. 2026-08-17 13:44 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  42. 2026-08-16 14:53 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  43. 2026-08-16 02:11 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  44. 2026-08-15 01:27 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  45. 2026-08-13 21:57 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  46. 2026-08-12 13:48 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  47. 2026-08-11 13:38 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  48. 2026-08-09 13:44 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  49. 2026-08-08 16:34 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  50. 2026-08-07 16:24 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  51. 2026-08-06 13:44 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  52. 2026-08-05 19:15 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  53. 2026-08-04 15:06 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  54. 2026-08-04 10:34 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
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  56. 2026-08-02 02:24 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  57. 2026-08-01 04:13 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  58. 2026-07-30 16:25 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  59. 2026-07-30 01:28 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  60. 2026-07-28 15:33 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  61. 2026-07-25 14:15 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  62. 2026-07-24 14:15 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  63. 2026-07-23 14:16 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  64. 2026-07-23 02:07 UTCEG score recompute
  65. 2026-07-22 22:54 UTCEG score recompute▲ 1.40
  66. 2026-07-22 14:06 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
  67. 2026-07-21 15:22 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  68. 2026-07-20 17:05 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  69. 2026-07-19 14:29 UTCEPSS rescoreEPSS 1.1% · 62nd percentile
  70. 2026-07-19 02:27 UTCEPSS rescoreEPSS 1.1% · 61st percentile

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Frequently asked(5)

What is CVE-2022-20737?
CVE-2022-20737 is a high-severity vulnerability; its CVE record was published on May 3, 2022. A vulnerability in the handler for HTTP authentication for resources accessed through the Clientless SSL VPN portal of Cisco Adaptive Security Appliance (ASA) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device or to obtain…
When was CVE-2022-20737 made public?
CVE-2022-20737 was made public on April 27, 2022: that is the date its CVE record's CNA, Cisco Systems, Inc., gives for when the vulnerability was made public. The CVE record itself was published on May 3, 2022. EchelonGraph's copy of the record carries a last-modified date of November 21, 2024; the record at its source may have been updated since.
Is CVE-2022-20737 actively exploited?
CVE-2022-20737 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.2% probability of exploitation in the next 30 days (67th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2022-20737?
CVE-2022-20737 has a CVSS v3 base score of 8.5 (NVD).
How do I remediate CVE-2022-20737?
No fix for CVE-2022-20737 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix.

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