CVE-2021-35247
Improper Input Validation Vulnerability in Serv-U
- Medium 4.3
- Exploited: added to CISA KEV 21 Jan 2022
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.
Key facts
- Published
- 7 Jan 2022
- Last changed
- 21 Oct 2025
- Assigned by
- SolarWinds
- KEV added
- 21 Jan 2022
- KEV fix due
- 4 Feb 2022
- EPSS
- 3.642% likely to be exploited in the next 30 days, higher than 89.754% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: active; Automatable: no; Technical impact: partial
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 4.3CVSS 3.1, Mediumfrom the CNA (SolarWinds)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
What to do
- Apply updates per vendor instructions.CISA KEV required action
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| SolarWinds | Serv-U |
|
Timeline
- 7 Jan 2022 Published
- 21 Jan 2022 CVE-2021-35247 added to CISA KEV
- 21 Jan 2022 Added to the CISA KEV catalogue