Vulnerability · CVE-2021-35247
SolarWinds Serv-U Improper Input Validation Vulnerability
Published Jan 10, 2022 · catalog updated Jun 16, 2026 · SolarWinds Serv-U
Patch now
CVE-2021-35247 is in the CISA known-exploited catalog, due Feb 4, 2022. Confirm SolarWinds Serv-U against the vendor advisory and apply that fix. The CVSS score does not change the priority.
Gaps on this record
- No version range is stored. A customer cannot check an installed version against this record.
- Severity
- Medium5.3
- Known exploitation
- CISA KEV and VulnCheck KEV
- EPSS
- 3.45%
- Remediation
- Remediation guidance
- Affected products
- cpe solarwinds/serv-u · vendor SolarWinds Serv-U
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.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe solarwinds/serv-uversion unspecified
- vendor SolarWinds Serv-Uversion unspecified
How to fix CVE-2021-35247
Recommended remediation
Apply updates per vendor instructions. CISA due date Feb 4, 2022.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
CVE-2021-35247 is in the CISA known-exploited catalog, due Feb 4, 2022. Confirm SolarWinds Serv-U against the vendor advisory and apply that fix. The CVSS score does not change the priority.
Which versions are affected?
Affected version ranges are not on this record. Apply updates per vendor instructions.
What should an analyst verify?
CWE-20: Improper Input Validation. EPSS 3.45%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Jan 10, 2022 · Catalog
Detected
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 schedu
Jan 21, 2022 · CISA KEV
Known exploited
Apply updates per vendor instructions.
Feb 4, 2022 · CISA KEV
Remediation due
Apply updates per vendor instructions.
Jun 16, 2026 · Catalog
Updated
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 schedu
Sources
- CISA KEVConfirmed exploitationCVE-2021-35247
SolarWinds Serv-U versions 15.2.5 and earlier contain an improper input validation vulnerability that allows attackers to build and send queries without sanitization.
cisa.gov - CVE.orgVulnerability recordCVE-2021-35247
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2021-35247
30-day exploitation probability 3.5%
first.org - NIST NVDVulnerability recordCVE-2021-35247
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 ignor
nvd.nist.gov - VulnCheck KEVConfirmed exploitationCVE-2021-35247
SolarWinds Serv-U versions 15.2.5 and earlier contain an improper input validation vulnerability that allows attackers to build and send queries without sanitization.
vulncheck.com
References
Freshness
Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.