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CVE-2017-9461: smbd in Samba before 4.4.10 and 4.5.x before 4.5.6 has a denial of service vulnerability (fd_open_atomic in...

smbd in Samba before 4.4.10 and 4.5.x before 4.5.6 has a denial of service vulnerability (fd_open_atomic infinite loop with high CPU usage and memory consumption) due to wrongly handling dangling symlinks.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a denial-of-service flaw in Samba's smbd service. Affected servers can enter an infinite loop when handling dangling symbolic links, causing high CPU and memory consumption. The business impact is service disruption for Samba-backed file sharing, not data theft based on the provided sources.

Executive priority

Treat as a service availability risk. It should be remediated in normal patch cycles, faster for critical file servers or SMB services reachable by broad user populations.

Technical view

CVE-2017-9461 affects smbd in Samba before 4.4.10 and Samba 4.5.x before 4.5.6. The vulnerable fd_open_atomic handling of dangling symlinks can loop indefinitely, consuming CPU and memory. The provided sources do not include CVSS, CWE, exploit prerequisites, or detailed attack conditions.

Likely exposure

Exposure is likely limited to systems running affected Samba smbd versions, especially Samba file-sharing servers. The bundle does not identify specific downstream products, configurations, or whether authenticated share access is required.

Exploitation context

CISA KEV is false, and the provided source bundle does not cite active exploitation. SecurityFocus, Samba, Red Hat, and Debian references indicate public disclosure and vendor updates, but no weaponized exploitation evidence is provided here.

Researcher notes

The strongest source detail is the version boundary and root cause: fd_open_atomic mishandles dangling symlinks. Missing evidence includes CVSS, CWE, required privileges, remote/local reachability, and confirmed exploitation status.

Mitigation direction

  • Upgrade Samba to 4.4.10, 4.5.6, or later supported fixed releases.
  • Apply vendor-backported Samba security updates from Red Hat or Debian where applicable.
  • Prioritize externally reachable or business-critical Samba file servers first.
  • If immediate upgrade is blocked, check current Samba and OS vendor guidance.

Validation and detection

  • Inventory all hosts running smbd and record Samba package versions.
  • Confirm no host runs Samba before 4.4.10 or 4.5.x before 4.5.6.
  • Verify Red Hat or Debian advisory packages are installed where applicable.
  • Review smbd CPU and memory telemetry for unexplained sustained spikes.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

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CVE-2017-9461 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
8Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.