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Full vulnerability report · 2026
CVE-2026-28318High confidence

SolarWinds Serv-U Uncontrolled Resource Consumption Vulnerability

SolarWinds · Serv-U

7.5HighCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2026-06-19 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Critical, raised one band.upgradedsince 5 Jun 2026

Evidence used

  • CISA confirms exploitation in the wild.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 1.94% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs SolarWinds Serv-U and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-34268

CISA KEV mirrored by ENISA

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

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 5 Jun 2026. Evidence sources: cisa_kev.
ENISA score
7.5 · CVSS 3.1
Advisory evidence
1 linked advisory record
Explicit mitigation evidence

Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.

  • csaf_ncscnl · NCSC-2026-0176Kwetsbaarheid verholpen in SolarWinds Serv-U
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2026-06-19 as the remediation due date.

Patch available
01

What, why and how

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.

What

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.

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

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.

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-06-05.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Uncontrolled Resource Consumption → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-400 ↗

CWE-400: Uncontrolled Resource Consumption. The product does not properly control the allocation and maintenance of a limited resource.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-400CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-34268Known-exploited evidence recorded

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

Official EUVD record ↗
BSI · German · WID-SEC-2026-1787SolarWinds Serv-U: Schwachstelle ermöglicht Denial of Service

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in SolarWinds Serv-U ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-549SolarWinds security advisory (AV26-549) - Update 1

Between June 2 and 3, 2026, SolarWinds published security advisories to address vulnerabilities in the following products: On June 5, 2026, Cybersecurity and Infrastructure Security Agency (CISA) added CVE-2026-28318 to their Known Exploited Vulnerabilities (KEV) Database.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260610Security Bulletin 10 Jun 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 10 Jun 2026, published on 10 June 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-018338SolarWindsのServ-Uにおけるリソースの枯渇に関する脆弱性

SolarWinds Serv-Uには、Content-Encoding: deflateを使用した認証なしの特別に細工されたPOSTリクエストにより、Serv-Uサービスがクラッシュする脆弱性があります。アップデートを適用できない場合は、SolarWinds Trust Centerで提供されている緩和手順に従い、顧客環境を保護してください。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6833SolarWinds 제품 보안 업데이트 권고

SolarWinds Serv-U에서 발생하는 Uncontrolled Resource Consumption 취약점(CVE-2026-28318) [1][2]

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6832美 CISA 발표 주요 Exploit 정보공유(Update. 2026-06-05)

SolarWinds Serv-U Uncontrolled Resource Consumption Vulnerability

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0176Kwetsbaarheid verholpen in SolarWinds Serv-U

SolarWinds Serv-U contains a vulnerability where specially crafted POST requests with Content-Encoding: deflate can cause an unauthenticated service crash, with mitigation details available on the SolarWinds Trust Center.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Serv-U: 15.5.4 and previous versions
Fixed
Upgrade to SolarWinds Serv-U 15.5.4 Hotfix 1. Use the mitigation steps until the upgrade is possible.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 4 Jun 2026 · Last source change 6 Jun 2026, 03:55 UTC · CWE-400 · Uncontrolled Resource Consumption

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-34268
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added remediation: solarwinds.com/CVE-2026-28318.
    Before
    vendor advisory: solarwinds.com/CVE-2026-28318
    After
    remediation: solarwinds.com/CVE-2026-28318 · vendor advisory: solarwinds.com/CVE-2026-28318
    psirt@solarwinds.com ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    15.5.4 and previous versions · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Serv-U: 15.5.4 and previous versions · Fixed: Upgrade to SolarWinds Serv-U 15.5.4 Hotfix 1. Use the mitigation steps until the upgrade is possible.
    CNA ↗
  4. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    psirt@solarwinds.com ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-34268↗CISA KEV record↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-28318 · cve.blacktree.nl