CVE-2026-20028

MEDIUMPre-NVD 5.05.0—
EchelonGraph scoreMEDIUM confidence

Score 5.0 from GitHub Security Advisory published 2026-08-05. A secondary CVSS source baseline 5.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
5.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.0Exploit: 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 network driver of Cisco Terminal Service (TS) Agent could allow an authenticated, remote attacker to bypass firewall rules that are associated with the account of the attacker. This vulnerability is due to an incorrect mapping of network connections to user accounts. An attacker with at least user-level credentials could exploit this vulnerability by sending crafted network traffic to an affected device. A successful exploit could allow the attacker to inherit the firewall rules associated with a different user in the system.

CVSS v3
5.0
EG Score
5.0MEDIUMmedium confidence
EG Risk
23
EG Risk 23/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity50% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
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
0.3%
EPSS %ILE
25th
KEV
Not listed

CISA SSVCTrack 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). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 5, 2026

Last Modified

August 6, 2026

Advisory Details (1)

Auto-updated Aug 5, 2026
No patch confirmed yet.
generic

Cisco Terminal Services Agent Firewall Rules Bypass Vulnerability

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ts-agent-fw-bypass-MYBTMrev

Vendor Advisories for CVE-2026-20028(2)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 65× 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 150 total refreshes for this CVE.

  1. 2026-10-04 23:21 UTCEPSS rescore
  2. 2026-10-04 06:00 UTCEG score recompute
  3. 2026-10-04 06:00 UTCGHSA enrichment
  4. 2026-10-02 09:55 UTCEG score recompute
  5. 2026-10-02 09:55 UTCGHSA enrichment
  6. 2026-10-01 19:49 UTCEPSS rescore
  7. 2026-10-01 02:17 UTCEG score recompute
  8. 2026-10-01 02:17 UTCGHSA enrichment
  9. 2026-09-30 15:03 UTCEPSS rescore
  10. 2026-09-29 15:21 UTCEPSS rescore
  11. 2026-09-29 06:15 UTCEG score recompute
  12. 2026-09-29 06:15 UTCGHSA enrichment
  13. 2026-09-28 13:51 UTCEPSS rescore
  14. 2026-09-27 17:42 UTCEG score recompute
  15. 2026-09-27 17:42 UTCGHSA enrichment
  16. 2026-09-27 13:47 UTCEPSS rescore
  17. 2026-09-26 15:58 UTCEPSS rescore
  18. 2026-09-26 00:26 UTCEPSS rescore
  19. 2026-09-25 04:31 UTCEG score recompute
  20. 2026-09-25 04:31 UTCGHSA enrichment
  21. 2026-09-24 14:03 UTCEPSS rescore
  22. 2026-09-24 00:20 UTCEG score recompute
  23. 2026-09-24 00:20 UTCGHSA enrichment
  24. 2026-09-23 00:54 UTCEG score recompute
  25. 2026-09-23 00:54 UTCGHSA enrichment
Show 75 more
  1. 2026-09-22 01:29 UTCEG score recompute
  2. 2026-09-22 01:29 UTCGHSA enrichment
  3. 2026-09-20 20:15 UTCEPSS rescore
  4. 2026-09-20 03:14 UTCEG score recompute
  5. 2026-09-20 03:13 UTCGHSA enrichment
  6. 2026-09-19 03:23 UTCEG score recompute
  7. 2026-09-19 03:23 UTCGHSA enrichment
  8. 2026-09-18 19:27 UTCEPSS rescore
  9. 2026-09-18 03:16 UTCEG score recompute
  10. 2026-09-18 03:16 UTCGHSA enrichment
  11. 2026-09-17 03:51 UTCEG score recompute
  12. 2026-09-17 03:51 UTCGHSA enrichment
  13. 2026-09-16 14:07 UTCEPSS rescore
  14. 2026-09-16 05:14 UTCEPSS rescore
  15. 2026-09-16 03:11 UTCEG score recompute
  16. 2026-09-16 03:11 UTCGHSA enrichment
  17. 2026-09-15 03:03 UTCGHSA enrichment
  18. 2026-09-14 03:38 UTCEG score recompute
  19. 2026-09-14 03:38 UTCGHSA enrichment
  20. 2026-09-13 16:46 UTCEPSS rescore
  21. 2026-09-13 04:13 UTCEG score recompute
  22. 2026-09-13 04:13 UTCGHSA enrichment
  23. 2026-09-12 15:00 UTCEPSS rescore
  24. 2026-09-12 04:38 UTCEG score recompute
  25. 2026-09-12 04:38 UTCGHSA enrichment
  26. 2026-09-11 14:52 UTCEPSS rescore
  27. 2026-09-11 09:36 UTCEPSS rescore
  28. 2026-09-11 05:12 UTCEG score recompute
  29. 2026-09-11 05:12 UTCGHSA enrichment
  30. 2026-09-10 09:34 UTCEPSS rescore
  31. 2026-09-10 05:47 UTCGHSA enrichment
  32. 2026-09-09 06:22 UTCEG score recompute
  33. 2026-09-09 06:22 UTCGHSA enrichment
  34. 2026-09-08 22:00 UTCEPSS rescore
  35. 2026-09-07 18:16 UTCEG score recompute
  36. 2026-09-07 18:16 UTCGHSA enrichment
  37. 2026-09-07 16:01 UTCEPSS rescore
  38. 2026-09-06 13:47 UTCEPSS rescore
  39. 2026-09-06 08:21 UTCEG score recompute
  40. 2026-09-06 08:21 UTCGHSA enrichment
  41. 2026-09-05 08:56 UTCEG score recompute
  42. 2026-09-05 08:56 UTCGHSA enrichment
  43. 2026-09-04 09:30 UTCGHSA enrichment
  44. 2026-09-03 06:47 UTCEG score recompute
  45. 2026-09-03 06:47 UTCGHSA enrichment
  46. 2026-09-02 14:11 UTCEPSS rescore
  47. 2026-09-01 22:14 UTCEG score recompute
  48. 2026-09-01 22:14 UTCGHSA enrichment
  49. 2026-09-01 13:53 UTCEPSS rescore
  50. 2026-09-01 04:39 UTCEPSS rescore
  51. 2026-08-31 22:48 UTCGHSA enrichment
  52. 2026-08-30 20:47 UTCEG score recompute
  53. 2026-08-30 20:47 UTCGHSA enrichment
  54. 2026-08-30 19:17 UTCEPSS rescore
  55. 2026-08-30 01:22 UTCEPSS rescore
  56. 2026-08-29 21:22 UTCEG score recompute
  57. 2026-08-29 21:22 UTCGHSA enrichment
  58. 2026-08-28 21:41 UTCEPSS rescore
  59. 2026-08-28 03:39 UTCEG score recompute
  60. 2026-08-28 03:39 UTCGHSA enrichment
  61. 2026-08-27 14:25 UTCEPSS rescore
  62. 2026-08-27 04:14 UTCEG score recompute
  63. 2026-08-27 04:14 UTCGHSA enrichment
  64. 2026-08-26 14:46 UTCEPSS rescore
  65. 2026-08-26 04:39 UTCEG score recompute
  66. 2026-08-26 04:39 UTCGHSA enrichment
  67. 2026-08-25 13:48 UTCEPSS rescore
  68. 2026-08-25 05:10 UTCEG score recompute
  69. 2026-08-25 05:10 UTCGHSA enrichment
  70. 2026-08-24 05:45 UTCGHSA enrichment
  71. 2026-08-23 06:19 UTCEG score recompute
  72. 2026-08-23 06:19 UTCGHSA enrichment
  73. 2026-08-23 00:19 UTCEPSS rescore
  74. 2026-08-22 06:54 UTCEG score recompute
  75. 2026-08-22 06:54 UTCGHSA enrichment

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Frequently asked(5)

What is CVE-2026-20028?
CVE-2026-20028 is a medium vulnerability published on August 5, 2026. A vulnerability in the network driver of Cisco Terminal Service (TS) Agent could allow an authenticated, remote attacker to bypass firewall rules that are associated with the account of the attacker. This vulnerability is due to an incorrect mapping of network connections to user accounts. An…
When was CVE-2026-20028 disclosed?
CVE-2026-20028 was first published on August 5, 2026, with the most recent update on August 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-20028 actively exploited?
CVE-2026-20028 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (25th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-20028?
CVE-2026-20028 has a CVSS base score of 5.0 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-20028?
No fix for CVE-2026-20028 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. The vendor advisories EchelonGraph has for CVE-2026-20028 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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