CVE-2026-20028

MEDIUMPre-NVD 5.05.0—
EchelonGraph scoreHIGH 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%CVSS: 5.0Exploit: None knownExposed: 0

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

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
5.0(high)
EG Risk
23(Track)
EG Risk 23/100SSVC: Track

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%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
17%
KEV
Not listed

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 23× 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.

  1. 2026-08-21 07:29 UTCEG score recompute
  2. 2026-08-21 07:29 UTCGHSA enrichment
  3. 2026-08-20 22:55 UTCEPSS rescore
  4. 2026-08-20 08:04 UTCEG score recompute
  5. 2026-08-20 08:04 UTCGHSA enrichment
  6. 2026-08-19 17:03 UTCEPSS rescore
  7. 2026-08-19 08:38 UTCEG score recompute
  8. 2026-08-19 08:38 UTCGHSA enrichment
  9. 2026-08-18 13:48 UTCEPSS rescore
  10. 2026-08-18 09:13 UTCEG score recompute
  11. 2026-08-18 09:13 UTCGHSA enrichment
  12. 2026-08-17 13:47 UTCEPSS rescore
  13. 2026-08-17 09:46 UTCEG score recompute
  14. 2026-08-17 09:46 UTCGHSA enrichment
  15. 2026-08-16 14:56 UTCEPSS rescore
  16. 2026-08-16 10:21 UTCEG score recompute
  17. 2026-08-16 10:21 UTCGHSA enrichment
  18. 2026-08-16 02:14 UTCEPSS rescore
  19. 2026-08-15 10:56 UTCEG score recompute
  20. 2026-08-15 10:56 UTCGHSA enrichment
  21. 2026-08-15 01:30 UTCEPSS rescore
  22. 2026-08-14 11:30 UTCEG score recompute
  23. 2026-08-14 11:30 UTCGHSA enrichment
  24. 2026-08-13 22:00 UTCEPSS rescore
  25. 2026-08-13 12:05 UTCEG score recompute
Show 24 more
  1. 2026-08-13 12:05 UTCGHSA enrichment
  2. 2026-08-12 13:50 UTCEPSS rescore
  3. 2026-08-12 12:40 UTCEG score recompute
  4. 2026-08-12 12:40 UTCGHSA enrichment
  5. 2026-08-11 13:42 UTCEPSS rescore
  6. 2026-08-11 13:11 UTCEG score recompute
  7. 2026-08-11 13:11 UTCGHSA enrichment
  8. 2026-08-11 00:00 UTCEPSS rescore
  9. 2026-08-10 13:46 UTCGHSA enrichment
  10. 2026-08-09 14:21 UTCEG score recompute
  11. 2026-08-09 14:21 UTCGHSA enrichment
  12. 2026-08-09 13:46 UTCEPSS rescore
  13. 2026-08-08 16:37 UTCEPSS rescore
  14. 2026-08-08 14:56 UTCEG score recompute
  15. 2026-08-08 14:56 UTCGHSA enrichment
  16. 2026-08-07 15:30 UTCGHSA enrichment
  17. 2026-08-06 16:05 UTCEG score recompute
  18. 2026-08-06 16:05 UTCGHSA enrichment
  19. 2026-08-06 13:46 UTCEPSS rescore
  20. 2026-08-05 18:31 UTCEG score recompute
  21. 2026-08-05 18:31 UTCGHSA enrichment
  22. 2026-08-05 17:30 UTCEG score recompute
  23. 2026-08-05 16:52 UTCEG score recompute
  24. 2026-08-05 16:50 UTCMITRE cvelistV5first tracked

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 in the National Vulnerability Database 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% probability of exploitation in the next 30 days, which ranks it in the top 83.1% of all scored CVEs.
What is the CVSS score of CVE-2026-20028?
CVE-2026-20028 has a CVSS v3 base score of 5.0 (NVD).
How do I remediate CVE-2026-20028?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-20028, 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

Explore the affected products and dependency analysis for CVE-2026-20028

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