Description
A remote authenticated attacker with write access to a PI Server could trick a user into interacting with a PI Web API endpoint and redirect them to a malicious website. As a result, a victim may disclose sensitive information to the attacker or be provided with false information.
Timeline
ID reserved
By icscert
- 10 days later
· 10 days later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| icscertCNA (assigner) | 3.1 | Medium6.9 | CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium4.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.71% · top 46% of all CVEs (8 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.9.
Weakness
Affected products
- affected All versions – ≤ 2019 SPI
What to do
Workaround: OSIsoft recommends upgrading to PI Web API 2021. Additional information can be found in the OSIsoft PI Web API security bulletin (registration required). OSIsoft recommends applying the following workaround in PI Web API to help reduce the risk: Remove the OSIsoft.REST.Documentation.dll from the PI Web API installation directory. The PI Web API installation directory is available at this registry entry: \\HKLM\SOFTWARE\PISystem\WebAPI\InstallationDirectory The default PI Web API installation directory is: C:\Program Files\PIPC\WebAPI Removing this file will cause built-in documentation to no longer be available. Navigating to the PI Web API endpoint with a browser will result in an error; however, the PI Web API will continue to function as a REST API Documentation can be found at the OSIsoft website. Alternately, users are encouraged to limit access to PI Web API built-in documentation to dedicated development environments OSIsoft recommends users employ the following defense measures to lower the impact of exploitation for PI Web API: Avoid adding authentication type “Anonymous” in PI Web API configuration settings to limit exposure to authenticated users only, Consider using a web application firewall to block html responses from PI Web API servers, Audit the AF hierarchy to ensure there are no unauthorized databases, elements, or attributes, For Kerberos authentication configurations, use Group Policy to deny network authentication to PI Server Administrator accounts on the PI Web API server. See the OSIsoft customer portal knowledge article for additional details and associated security updates (registration required).
References (1)
- https://us-cert.cisa.gov/ics/advisories/icsa-21-313-06 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-43549)Record last updated .