Assessment
Why it matters
CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 8.4%; technical severity is CVSS 7.5.
SolarWinds Serv-U is susceptible to specially crafted POST requests that crash the Serv-U service without authentication using Content-Encoding: deflate. Mitigation steps are provided to secure customer environments in the SolarWinds Trust Center if you are unable to deploy the update
Who should care
- Teams operating Serv-U
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether Serv-U is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- Vendor advisory from www.solarwinds.com
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Treatment intelligence
Remediation intelligence
Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.
Verification noteAutomated link verification has not completed for this guidance yet.
Technical details
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CWE
- CWE-400
- Affected versions
- SolarWinds Serv-U (End Excluding 15.5.4 | Version 15.5.4)
- Fixed versions
- SolarWinds Serv-U (Fixed from 15.5.4)
- Published
- 4 June 2026
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
Signal timeline
- Added to CISA KEV
- Latest EPSS score: 8.4%
- Signal calculated at 68