What’s Vulnerable › Vulnerabilities

CVE-2021-35247: SolarWinds Serv-U Improper Input Validation Vulnerability

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2022-01-21
• EPSS: 3.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-01-10 · updated 2026-06-17
• Weakness: CWE-20

Description

Serv-U web login screen to LDAP authentication was allowing characters that were not sufficiently sanitized. SolarWinds has updated the input mechanism to perform additional validation and sanitization. Please Note: No downstream affect has been detected as the LDAP servers ignored improper characters. To insure proper input validation is completed in all environments. SolarWinds recommends scheduling an update to the latest version of Serv-U.

Affected products

• SolarWinds Serv-U: before 15.3 — fixed in 15.3

How to fix

Upgrade to a fixed version: SolarWinds Serv-U 15.3. Check the vendor advisory for mitigations.

References

• https://documentation.solarwinds.com/en/success_center/servu/content/release_notes/servu_15-3_release_notes.htm
• https://www.solarwinds.com/trust-center/security-advisories/cve-2021-35247
• https://documentation.solarwinds.com/en/success_center/servu/content/release_notes/servu_15-3_release_notes.htm
• https://www.solarwinds.com/trust-center/security-advisories/cve-2021-35247
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-35247

Get alerted when CVE-2021-35247 or the next vulnerability affects your stack