NVD / CVE Program· CNA SolarWinds

CVE-2026-28318: SolarWinds Serv-U Unauthenticated Denial of Service Vulnerability

Noroxi assessment

Priority: This week (action score 73/100)

CISA has confirmed exploitation in the wild (Jun 5, 2026). Remediation deadline for US federal agencies: Jun 19, 2026.
Probability of exploitation in the next 30 days: 43.6% (FIRST EPSS); higher than 98.7% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
According to the record, no fixed version is available yet.

Don’t wait for the next maintenance window. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

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

HighCVSS 7.5 · v3.1KEVWeaponized No fix recorded

BDU:2026-07860

Published: Jun 4, 2026
Updated: Oct 21, 2026
EPSS: 43.6% · 98th percentile
CWE: CWE-400

Report tools

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Action score

This week

Don’t wait for the next maintenance window.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 30 / 30 · Listed
EPSS: 13 / 30 · 43.6%

CISA SSVC decision

Exploitation: active
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · SolarWinds: 7.5; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Jun 5, 2026. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Jun 19, 2026.

Get told when this record changes

In CISA KEV: exploitation in the wild confirmed
Weaponized exploit exists
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
solarwinds	serv-u	cpe:2.3:a:solarwinds:serv-u

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

solarwinds serv-ubefore 15.5.4
solarwinds serv-u15.5.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (SolarWinds). Independent of NVD's CPE analysis and usually ahead of it.

SolarWinds Serv-U
- up to and including 15.5.4affected

Same product

solarwinds: all records

Other highest-scoring records for the same primary product.

CVE-2021-35211Serv-U Remote Memory Escape VulnerabilityKEV
97Now
CVE-2024-28995SolarWinds Serv-U L Directory Transversal VulnerabilityKEV
90Now
CVE-2021-35247Improper Input Validation Vulnerability in Serv-UKEV
60This week

Published before and after this one in the same product

← EarlierCVE-2025-40540Feb 24, 2026 · SolarWinds Serv-U Type Confusion Remote Code Execution Vulnerability
28Monitor
← EarlierCVE-2025-40541Feb 24, 2026 · SolarWinds Serv-U Insecure Direct Object Reference (IDOR) Remote Code Execution Vulnerability
28Monitor
Later →CVE-2026-28302Jul 21, 2026 · SolarWinds Serv-U Insecure Direct Object Reference (IDOR) Vulnerability
36Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

Proof-of-concept repository on GitHub ×2

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Proof-of-concept repository on GitHub	stars:1	2026-06-10
Proof-of-concept repository on GitHub	stars:1	2026-06-12

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedJun 4, 2026
CISA KEVJun 5, 2026same day
First PoCJun 10, 2026+5 d
TodayNov 5, 2026+154 d

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

—

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

CVE-2026-2830247 days apartSolarWinds Serv-U Insecure Direct Object Reference (IDOR) Vulnerability
36Monitor
CVE-2026-2830447 days apartSolarWinds Serv-U Remote Code Execution Vulnerability
36Monitor
CVE-2026-2830547 days apartSolarWinds Serv-U Insecure Direct Object Reference (IDOR) Vulnerability
36Monitor
CVE-2026-2830847 days apartSolarWinds Serv-U Insecure Direct Object Reference (IDOR) Vulnerability
36Monitor

Bug bounty scope

SolarWinds VDPIntigriti · disclosure only (VDP)

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

documentation.solarwinds.com/en/success_center/servu/content/release_notes/servu_15-5-4-hotfix-1_release_notes.htm

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records