Security Digest · Vulnerability record · Known exploited
CVE-2026-28318: SolarWinds Serv-U Uncontrolled Resource Consumption Vulnerability
Exploited in the wild (CISA KEV). SolarWinds Serv-U is susceptible to specially crafted POST requests that crash the Serv-U service without authentication using Content-Encoding: deflate.
CISA KEV · added 2026-06-05 CVSS 7.5 High EPSS 1.9% · p80
Should you act?
Exploited: patch now if you run it
CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Yes, if you run SolarWinds Serv-U. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-06-05, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-06-19; treat that as the outer limit, not the target.
- EPSS 1.9%, percentile 80: FIRST’s model estimates a 1.9% chance of exploitation activity in the next 30 days, higher than 80% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
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
CISA’s summary
SolarWinds Serv-U contains an uncontrolled resource consumption vulnerability that allows specially crafted POST requests using the Content-Encoding: deflate header to crash the Serv-U service without authentication.
Weakness type: CWE-400.
Product: SolarWinds Serv-U · Assigned by: SolarWinds · Published: 2026-06-04
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| SolarWinds | Serv-U | <= 15.5.4 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| SolarWinds | 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: added 2026-06-05; federal due date 2026-06-19. Known ransomware use: Unknown.
- 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.
- CISA SSVC assessment: exploitation active, automatable yes, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 1.94% probability of exploitation activity in the next 30 days; percentile 80.
Timeline
- — CVE record published by SolarWinds
- — Added to CISA’s Known Exploited Vulnerabilities catalog
- — CISA remediation deadline for US federal agencies
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- Listed in CISA KEV notes (solarwinds.com) solarwinds.com
- Listed in CISA KEV notes (documentation.solarwinds.com) documentation.solarwinds.com
Vulnerability records
- CVE.org record CVE-2026-28318 cve.org
- NVD entry CVE-2026-28318 nvd.nist.gov
Government
Other references from the CVE record and advisory
- solarwinds.com solarwinds.com
- documentation.solarwinds.com documentation.solarwinds.com
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