SolarWinds Serv-U is widely deployed; arbitrary file R/W enabling root code execution can disrupt organizations and warrant broad notification.
CVE-2026-28321
Broken access control in SolarWinds Serv-U allows arbitrary file R/W and root code execution.
Is CVE-2026-28321 being exploited?
Not confirmed. CVE-2026-28321 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.58% probability of exploitation in the next 30 days.
How severe is CVE-2026-28321?
CVE-2026-28321 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-28321?
Yes. A fix has been recorded for CVE-2026-28321. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-28321 affect?
CVE-2026-28321 affects SolarWinds Serv-U (FTP/SFTP server) - Linux and Windows installations (impact lower on Windows). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-28321?
Apply vendor patch ASAP; if unavailable, disable Serv-U, restrict domain-admins, audit and rotate credentials.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Arbitrary file read/write enabling privilege escalation to root and remote code execution; attacker requires domain administrator access.
Immediate action required
- affected15.5.4 HF1 and below
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.