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Fencer Intel
medium 4.3

CVE-2021-35247 kev in the critical feed json

Improper Input Validation Vulnerability in Serv-U

published 4y ago modified 4mo ago also EUVD-2021-21890

cvss
4.3
version 3.1, CNA
cisa kev
Exploited
added 2022-01-21
epss
3.6%
EPSS 3.6% chance of exploitation in 30 days, percentile 89%
public exploits
0
none known

Summary

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.

Patch / fix

cisa required action Apply updates per vendor instructions.

  • SolarWinds Serv-U 15.3

Is CVE-2021-35247 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Timeline

  1. Published
  2. Added to CISA KEV
  3. CISA patch deadline
  4. CISA SSVC: exploitation active

Known exploited

Added
4y ago
Patch by
2022-02-04 (4y ago)
Ransomware
Not known
Required action
Apply updates per vendor instructions.
Vendor, product
SolarWinds, Serv-U
CISA name
SolarWinds Serv-U Improper Input Validation Vulnerability

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

3.64% chance of exploitation in the next 30 days, higher than 89% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N

Affected products

  • SolarWinds Serv-U

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.