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Full vulnerability report · 2026
CVE-2026-65641High confidence

A vulnerability allowing an unauthenticated network attacker to coerce SMB authentication from the service account

Veeam · One

Official source article: Veeam KB4905 ↗. Check the applicable product and release in the original source.

9.3CriticalCVSS 4.0
Recommended action
Within 72 hours

Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityCriticalOperational priority:Critical, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.54% 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.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Veeam One 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-2026-66760

No EUVD known-exploited evidence

A vulnerability allowing an unauthenticated network attacker to coerce SMB authentication from the service account.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
9.3 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 72 hours

Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.

Patch available
01

What, why and how

A vulnerability allowing an unauthenticated network attacker to coerce SMB authentication from the service account.

What

A vulnerability allowing an unauthenticated network attacker to coerce SMB authentication from the service account.

Why

The product requires authentication, but the product has an alternate path or channel that does not require authentication.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

A vulnerability allowing an unauthenticated network attacker to coerce SMB authentication from the service account.

Why

The product requires authentication, but the product has an alternate path or channel that does not require authentication.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

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.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

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 → Authentication Bypass Using an Alternate Path or Channel → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-288 ↗

CWE-288: Authentication Bypass Using an Alternate Path or Channel. The product requires authentication, but the product has an alternate path or channel that does not require authentication.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:L

Common Vulnerability Scoring System 4.0: 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.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VILowVulnerable-system integrity: A successful attack can cause a limited loss.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCHighSubsequent-system confidentiality: A successful attack can cause a major loss.SILowSubsequent-system integrity: A successful attack can cause a limited loss.SALowSubsequent-system availability: A successful attack can cause a limited 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.
NetworkUnauthenticatedCWE-288
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-66760Official EUVD mapping

A vulnerability allowing an unauthenticated network attacker to coerce SMB authentication from the service account.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3008Veeam ONE: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Veeam ONE ausnutzen, um Sicherheitsvorkehrungen zu umgehen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260902Security Bulletin 2 Sept 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 2 Sept 2026, published on 2 September 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1080Multiples vulnérabilités dans les produits Veeam

De multiples vulnérabilités ont été découvertes dans les produits Veeam. Elles permettent à un attaquant de provoquer une atteinte à la confidentialité des données et un contournement de la politique de sécurité.

Official advisory ↗
CSIRT Italia · Italian · aggiornamento-di-sicurezza-per-veeam-oneAggiornamento di sicurezza per Veeam ONE

Aggiornamento di sicurezza Veeam sana una vulnerabilità con gravità "critica" presente in Veeam ONE, soluzione di monitoraggio e analisi per infrastrutture virtuali e di backup. Tale vulnerabilità, qualora sfruttata, potrebbe consentire a un attaccante remoto non autenticato di eludere le funzionalità di sicurezza sul sistema interessato.

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
One: < 13.1, < 13.0.2
Fixed
Action
Apply the fixed release for the affected product branch as recorded by Veeam. Validate the exact product and build in the linked advisory before deployment.
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.
Official vendor articles2 stored documents

Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.

  • KB4858: List of Security Fixes and Improvements in Veeam ONE →Original publisher ↗Searchable text snapshot · Captured 26 Oct 2026Secure Cloud Storage Fully-managed cloud storage for offsite backup, cloud DR, clean room and more What We Protect Microsoft 365 Entra ID Salesforce Azure Kubernetes Google Cloud AWS Hypervisors On-Premises All Workloads Solutions Solutions Use Cases & Capabilities Ransomware Recovery Workload Mobility
  • KB4905: Vulnerability Resolved in Veeam ONE 13.1 Patch 0 →Original publisher ↗Searchable text snapshot · Captured 26 Oct 2026Secure Cloud Storage Fully-managed cloud storage for offsite backup, cloud DR, clean room and more What We Protect Microsoft 365 Entra ID Salesforce Azure Kubernetes Google Cloud AWS Hypervisors On-Premises All Workloads Solutions Solutions Use Cases & Capabilities Ransomware Recovery Workload Mobility
04

Evidence and provenance

Published 26 Aug 2026 · Last source change 27 Aug 2026, 15:04 UTC · CWE-288 · Authentication Bypass Using an Alternate Path or Channel

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 2026-08-27
European sourceENISA EUVD · EUVD-2026-66760
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled

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

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    < 13.1; < 13.0.2 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    < 13.1; < 13.0.2 · Fixed: Veeam ONE 13.0.2 Patch 1 (build 13.0.2.7159); Veeam ONE 13.1 Patch 0 (build 13.1.0.7233)
    Veeam ↗
  2. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    Veeam ↗
  3. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  4. ENISA EUVD mappingEUVD-2026-66760 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-66760"}
    ENISA EUVD ↗
  5. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
  6. CVSS scoreCVSS vector changed while the displayed base score remained 9.3.
    Before
    9.3 (CVSS 4.0 · CNA · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
    After
    9.3 (CVSS 4.0 · CNA · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:L)
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
Fixed release recorded from official guidance
ENISA EUVD · EUVD-2026-66760↗CVE authority or vendor reference · Veeam KB4905↗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-2026-65641 · cve.blacktree.nl