CVE-2026-28318 — SolarWinds Serv-U Uncontrolled Resource Consumption Vulnerability
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 exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Confirmed exploitation (CISA KEV)+35
- Public exploit/PoC (github)+6
- EPSS 1.9% (30-day exploitation probability)+12
- Technical severity (high)+6
- Automatable exploitation (SSVC)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
CISA required action CISA
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
US federal deadline: Jun 19, 2026 — passed 118 day(s) ago
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Solarwinds Serv-u).
- Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (denial of service), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Solarwinds | Serv-u | < 15.5.4version 15.5.4 | Vulnerable | NIST National Vulnerability Database |
| Solarwinds | Serv-u | version 15.5.4 and previous versions | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.5 | CVSS 3.1 | High | 3.9 | 3.6 | psirt@solarwinds.com via NIST National Vulnerability Database |
| 7.5 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 7.5 | CVSS 3.1 | High | — | — | SolarWinds via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: psirt@solarwinds.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
CISA KEV details CISA
CISA lists a CVE once it has evidence of exploitation against real targets.
CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.
Public exploits, PoCs and detection templates
Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.
- SolarWinds Serv-U CVE-2026-28318: unauthenticated Content-Encoding: deflate crash. Root-cause analysis (invalid free of an interior pointer -> heap corruption) + DoS-only PoC. Fixed in 15.5.4 Hotfix 1. ★ 1 Jun 10, 2026
- Safely detect whether a SolarWinds Serv-U host is vulnerable to CVE-2026-28318 ★ 1 Jun 12, 2026
Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.
EPSS over time FIRST
Oct 12, 2026 → Oct 14, 2026 · 3 reading(s) · max 1.94%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Track CPU/memory spikes and availability drops correlated with request patterns.
- Hunt retroactively in logs from before Jun 5, 2026 (KEV listing): exploitation may have started earlier.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · solarwinds/serv-u
- SSVC assessment updated
- Record published
- Affected products added · solarwinds/serv-u
- CVSS changed · 7.5
- Source status changed · → Analyzed
- Added to CISA KEV (detected)
- Record created in this database
- Added to CISA KEV catalog
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 13, 2026 – Oct 13, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
5 on the record
- www.solarwinds.com/trust-center/security-advisories/CVE-2026-28318
- www.cisa.gov/known-exploited-vulnerabilities-catalog
- documentation.solarwinds.com/en/success_center/servu/content/release_notes/servu_15-5-4-hotfix-1_r
- nvd.nist.gov/vuln/detail/CVE-2026-28318
- github.com/advisories/GHSA-4vx4-vp54-mwmc
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-28321 SolarWinds Serv-U Broken Access Control Vulnerability Jul 21, 2026
- Critical CVE-2026-28317 SolarWinds Serv-U Insecure Direct Object Reference (IDOR) Vulnerability Jul 21, 2026
- Critical CVE-2026-28313 SolarWinds Serv-U Insecure Direct Object Reference (IDOR) Vulnerability Jul 21, 2026
- Critical CVE-2026-28312 SolarWinds Serv-U Privilege Escalation Vulnerability Jul 21, 2026
- Critical CVE-2026-28314 SolarWinds Serv-U Insecure Direct Object Reference (IDOR) Vulnerability Jul 21, 2026
- Critical CVE-2026-28316 SolarWinds Serv-U Insecure Direct Object Reference (IDOR) Vulnerability Jul 21, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-28318 is "SolarWinds Serv-U Uncontrolled Resource Consumption Vulnerability", rated High. It affects Serv-u (Solarwinds); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 7.5 describes technical severity. EPSS 1.94% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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