A vulnerability in the boot process of Cisco IOS XR Software could allow an authenticated, local attacker with high privileges to bypass the Secure Boot functionality and load unverified software on an affected device. To exploit this vulnerability, the attacker must have root-system privileges on the affected device. This vulnerability is due to insufficient verification of modules in the software load process. An attacker could exploit this vulnerability by manipulating the loaded binaries to bypass some of the integrity checks that are performed during the booting process. A successful exploit could allow the attacker to control the boot configuration, which could enable them to bypass the requirement to run Cisco-signed images or alter the security properties of the running system. Note: This vulnerability affects Cisco IOS XR Software, not the Secure Boot feature. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Conclusion & alert: CVE-2025-20143 is rated Low Risk (27.3/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.10%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.04% | 0.10% | +0.06% |
| 2 | 2025-03-13 | — | 0.04% | — |
Full EPSS history (2 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.7 | 3.1 | MEDIUM |
|
0.8 | 5.9 | [email protected] |
| URL | Tags |
|---|---|
| https://blog.apnic.net/2024/09/02/crafting-endless-as-paths-in-bgp/ | Technical Description |
| https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sb-lkm-zNErZjbZ | Vendor Advisory |