CVE-2026-28318: SolarWinds Serv-U Uncontrolled Resource Consumption Vulnerability
SolarWinds · Serv-U · NVD published 2026-06-04 · posted 2026-06-05 · last modified 2026-10-21
What it is
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
| Weakness | CWE-400 |
|---|---|
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (source: [email protected]) |
| CISA due date | 2026-06-19 (for US federal agencies under BOD; a good deadline for everyone) |
| ATT&CK tactics | Impact |
Exploitation evidence
First exploit evidence seen: 2026-06-05 (earliest date across the sources below).
Exploited in the wild
- CISA KEV: listed since 2026-06-05. Source
Public exploit code
GitHub proof-of-concept repositories below quality bar
2 public repositories from 2 accounts, first seen 2026-06-10.
Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.
Sources: CISA KEV · nomi-sec/PoC-in-GitHub.
Defend the Chain
The attack chain for CVE-2026-28318 laid across the MITRE ATT&CK Enterprise tactics. Solid cards come from the MITRE CTID KEV mappings; dashed cards are inferred by CVERadar from the CWE or description. Correct defences are real ATT&CK mitigations for that technique.
Pick a red technique card on the board, then choose the defence that stops it.
Defend against T1499 Endpoint Denial of Service Inferred
Inferred from CWE CWE-400
How to fix it
CISA required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. (source: CISA KEV)
Fixed versions
- solarwinds serv-u: upgrade to 15.5.4 or later
Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.
Vendor advisories and patches
- https://www.solarwinds.com/trust-center/security-advisories/cve-2026-28318 (CISA KEV notes)
- https://documentation.solarwinds.com/en/success_center/servu/content/release_notes/servu_15-5-4-hotfix-1_release_notes.htm#link7 (CISA KEV notes)
- https://documentation.solarwinds.com/en/success_center/servu/content/release_notes/servu_15-5-4-hotfix-1_release_notes.htm (Release Notes)
- https://www.solarwinds.com/trust-center/security-advisories/CVE-2026-28318 (Vendor Advisory)
MITRE ATT&CK mitigations for this chain
- M1037 Filter Network Traffic (for T1499) : Leverage services provided by Content Delivery Networks (CDN) or providers specializing in DoS mitigations to filter traffic upstream from services. Filter boundary traffic by blocking source addresses sourcing the attack, blocking ports that are being targeted, or blocking protocols being used for transport. To defend
Detection Generic guidance
- Impact: Monitor service availability, unexpected encryption activity and mass file changes.
Response checklist Generic guidance
- Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
- Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
- Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
- Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.