---
title: "CVE-2021-35247: Improper Input Validation Vulnerability… | CubePath"
description: "Serv-U web login screen to LDAP authentication was allowing characters that were not sufficiently sanitized. SolarWinds has updated the input mechanism…"
language: en
source: https://cubepath.com/security/cve/CVE-2021-35247
---

# CVE-2021-35247: Improper Input Validation Vulnerability… | CubePath

## 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.

Official description from the CVE record, published by SolarWinds. Copyright © 1999-2026 The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CVE license. [View the record on cve.org](https://www.cve.org/CVERecord?id=CVE-2021-35247)

## Key data

### CVSS 3.1 Medium 4.3

Score published by SolarWinds in the CVE record.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

| Metric                 | Value     | What it means                                                                       |
| ---------------------- | --------- | ----------------------------------------------------------------------------------- |
| Attack vector          | Network   | The vulnerable component can be reached over a network, possibly from the Internet. |
| Attack complexity      | Low       | No special conditions are needed. The attack can be repeated at will.               |
| Privileges required    | None      | No account or privileges are needed.                                                |
| User interaction       | Required  | A user has to do something first, such as opening a file or following a link.       |
| Scope                  | Unchanged | The impact stays within the vulnerable component.                                   |
| Confidentiality impact | None      | No effect on the secrecy of data.                                                   |
| Integrity impact       | Low       | Limited effect on the trustworthiness of data.                                      |
| Availability impact    | None      | No effect on availability.                                                          |

CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at [first.org/cvss](https://www.first.org/cvss/) .

### EPSS

Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days.

Score

0.03642 (3.6% probability)

Percentile

89.7%

Scores of

Nov 10, 2026

Model

v2026.06.15

### CISA Known Exploited Vulnerabilities

This CVE is listed in the CISA KEV catalog.

Name in the catalog

SolarWinds Serv-U Improper Input Validation Vulnerability

Added to the catalog

Jan 21, 2022

Federal due date

Feb 4, 2022

### CISA assessment as of Jan 29, 2025

Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA.

Exploitation

Recorded by CISA as active

Automatable

no

Technical impact

partial

### Weakness (CWE)

CWE catalog version 5.0.

CWE names: Copyright © 2006-2026, The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CWE license.

- [CWE-20](https://cwe.mitre.org/data/definitions/20.html) Improper Input Validation

## Affected products

Products listed in the CVE record, as the CNA published them.

- SolarWinds Serv-U

  - affected: 15.2.5 and previous versions up to before 15.3

## References

Links listed in the CVE record. They lead to other sites, which CubePath does not control.

- [solarwinds.com/trust-center/security-advisories/cve-2021-35…](https://www.solarwinds.com/trust-center/security-advisories/cve-2021-35247)
- [documentation.solarwinds.com/en/success\_center/servu/conten…](https://documentation.solarwinds.com/en/success%5Fcenter/servu/content/release%5Fnotes/servu%5F15-3%5Frelease%5Fnotes.htm)

## Timeline

1. ID reserved Jun 22, 2021
2. Record published Jan 7, 2022
3. Added to CISA KEV Jan 21, 2022
4. Record last updated Oct 21, 2025

## Look up another CVE

## About CubePath

CubePath is a cloud provider with data centers in Europe and the United States. It offers VPS, bare metal servers and DDoS protection.

[Cloud VPS](https://cubepath.com/vps) [DDoS protection](https://cubepath.com/ddos-protection)

Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 20:03 UTC. [Sources and licenses](https://cubepath.com/security/cve/legal)