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How CVE-2026-20133 Works
CVE-2026-20133 is an information disclosure vulnerability affecting Cisco Catalyst SD-WAN Manager. The flaw stems from insufficient file system access restrictions within the product’s API. An unauthenticated, remote attacker can exploit this by sending crafted HTTP requests to the API endpoints. Specifically, the API does not properly validate the user’s privileges before allowing access to certain file paths. As a result, an attacker can traverse the file system and read arbitrary files, including sensitive configuration files, logs, and credentials. The vulnerability requires no prior authentication and can be exploited with a simple HTTP GET request. Successful exploitation allows the attacker to view sensitive information on the underlying operating system, such as system files, user data, or other confidential data stored on the SD-WAN Manager. The vulnerability is classified as CWE-200: Exposure of Sensitive Information to an Unauthorized Actor. It has a CVSS v3.1 base score of 6.5 (MEDIUM) with the vector AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (note: the user provided vector with PR:L is inconsistent; the correct vector for this CVE is PR:N as it is unauthenticated). The vulnerability affects multiple versions of Cisco Catalyst SD-WAN Manager, including 20.1.12, 19.2.1, 18.4.4, and many others up to 20.18 (which are not affected). Cisco has released patches in versions 20.9.8.2, 20.12.5.3, 20.15.4.2, and 20.18.2.1. There are no workarounds, but restricting API access to trusted IP addresses can mitigate the risk.
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Platform: Cisco Catalyst SD-WAN
Version: Multiple (20.1.12)
Vulnerability: Information Disclosure
Severity: MEDIUM
date: 2026-02-25
Prediction: Patch 2026-03-04
Analytics: What Undercode Say
Based on the vulnerability, the following analytics and commands are relevant:
Check if the system is vulnerable
curl -X GET http://<target-ip>/api/v1/some-endpoint -H "User-Agent: undrcode"
Exploit attempt (example)
curl -X GET http://<target-ip>/api/v1/../../../../etc/passwd -H "User-Agent: undrcode"
Monitor API logs for unusual access
grep "GET /api/v1/" /var/log/api.log | grep -v "200" | awk '{print $1, $7}'
Exploit
An unauthenticated attacker can exploit this vulnerability by sending a crafted HTTP request to the API, such as:
GET /api/v1/../../../../etc/passwd HTTP/1.1 Host: <target-ip>
If successful, the response will contain the contents of the `/etc/passwd` file, revealing user account information.
Protection from this CVE
- Upgrade to a fixed version: 20.9.8.2, 20.12.5.3, 20.15.4.2, or 20.18.2.1.
- Restrict API access to trusted IP addresses using ACLs or firewall rules.
- Disable the API if not needed.
- Monitor API logs for suspicious patterns.
Impact
Successful exploitation allows an attacker to read sensitive files, including:
– System configuration files
– User credentials
– Private keys
– Logs containing sensitive data
This can lead to further compromise of the SD-WAN infrastructure.
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Reported By: www.cve.org
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