Cisco IOS XE Web UI Command Injection Vulnerability
Cisco IOS XE contains a command injection vulnerability in the web user interface. When chained with CVE-2023-20198, the attacker can leverage the new local user to elevate privilege to root and write the implant to the file system. Cisco identified CVE-2023-20273 as the vulnerability exploited to deploy the implant. CVE-2021-1435, previously associated with the exploitation events, is no longer believed to be related to this activity.
- Vendor
- Cisco
- Product
- Cisco IOS XE Web UI
- CVSS
- 7.2
- EPSS (exploit probability)
- 92.9%
- Status
- kev
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2023-20273 being exploited?
Yes. CISA added CVE-2023-20273 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 92.9% (scored October 24, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-11-13. Full cross-catalog view: /kev-comparison
CVE-2023-20273 timeline
- Added to CISA KEV-2d (before NVD)
- Published to NVD
- First 0dayNews coverage+973d
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
What to do
CISA required actionVerify that instances of Cisco IOS XE Web UI are in compliance with BOD 23-02 and apply mitigations per vendor instructions. For affected products (Cisco IOS XE Web UI exposed to the internet or to untrusted networks), follow vendor instructions to determine if a system may have been compromised and immediately report positive findings to CISA.
US federal civilian agencies must remediate by (4 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Cisco IOS XE CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2023-20198 Cisco IOS XE Web UI Privilege Escalation Zero-Daywrite-up | [ CRITICAL ] | 10.0 | 99.8% | |
| CVE-2018-0174 Cisco IOS Software and Cisco IOS XE Software Improper Input Validation Vulnerability | [ HIGH ] | 8.6 | 7.6% | |
| CVE-2017-12319 Cisco IOS XE Software Ethernet Virtual Private Network Border Gateway Protocol Denial-of-Service Vulnerability | [ MEDIUM ] | 5.9 | 5.2% |