CVE-2021-35245Network attack vector

Host file alteration via unrestricted console operations

Published Dec 6, 2021 · Updated Sep 17, 2024

Broken access control in SolarWinds Serv-U before 15.2.5 allows remote authenticated users with console admin rights to alter host files. SolarWinds has not disclosed the defective authorization check; the console permits creation, movement, and deletion of any host file accessible to Serv-U. Exploitation requires an authenticated Serv-U Console administrator and user interaction, and its effect is bounded by the service account's host-file permissions.

CVSS severity8.4
High
EPSS probability1.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Broken access control in SolarWinds Serv-U before 15.2.5 allows remote authenticated users with console admin rights to alter host files. SolarWinds has not disclosed the defective authorization check; the console permits creation, movement, and deletion of any host file accessible to Serv-U. Exploitation requires an authenticated Serv-U Console administrator and user interaction, and its effect is bounded by the service account's host-file permissions.

The record

CVE
CVE-2021-35245
Published
Dec 6, 2021
Updated
Sep 17, 2024
Vendor
SolarWinds
Product
Serv-U
Classifications
CWE-284, T1565.001, T1485
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Dec 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=15.2.4 Hotfix 1 and previous versions <15.2.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

SolarWinds · Serv-Uversion=15.2.4 Hotfix 1 and previous versions <15.2.5

Published CVSS scores

6.8NVDAV:N/AC:L/Au:S/C:N/I:C/A:N
6.8NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N
8.4SolarWindsCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1565.001Stored Data Manipulation
T1485Data Destruction

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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