CVE-2026-20028
MEDIUM 5A 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.
No known exploitation, public exploit, or elevated probability at this time. Track for changes.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 17th percentile
Impact if exploited
5CVSS 3.1 · MEDIUM
- ConfidentialityNone
- IntegrityLow
- AvailabilityNone
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-20028/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-20028/poc.json
Weakness (CWE)
- CWE-266: Incorrect Privilege Assignment
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N
All CVSS metrics
- MEDIUM 5 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N - MEDIUM 5 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N