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CVE Record

CVE-2026-2340: Samba: vfs_worm does not block directory modification

A flaw was found in Samba’s vfs_worm module. The module is intended to provide write-once, read-many (WORM) protections by preventing modification of files after a configurable grace period. Due to insufficient validation during rename operations, an authenticated user with write access to a share could overwrite a protected file by renaming a newly created file over the existing WORM-protected file.

MediumCVSS 6.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2026-2340 weakens Samba’s WORM file protection. A user who already has write access to a Samba share may be able to replace a file that should have become immutable. This is most important where Samba shares are used for retention, audit, compliance, or tamper-resistant storage.

Executive priority

Prioritize where Samba WORM shares protect regulated, evidentiary, or business-critical records. This is not a broad unauthenticated takeover issue, but it can undermine integrity controls that management may rely on for retention and tamper resistance.

Technical view

Samba’s vfs_worm module insufficiently validates rename operations. After the configured grace period, protected files should not be modified, but an authenticated share user with write permission can overwrite a WORM-protected file by renaming a newly created file over it. Red Hat rates this medium, CVSS 6.5, CWE-280, with high integrity impact.

Likely exposure

Exposure is limited to systems running affected Red Hat Samba packages where vfs_worm is configured on writable shares. Red Hat lists affected RHEL 7, 8, 9, 10 streams and OpenShift Container Platform 4.19 rhcos. RHEL 6 status is listed as unknown in the provided data.

Exploitation context

The attacker must be authenticated and already have write access to the share. The issue is network-reachable through Samba, low complexity, and does not require user interaction. CISA KEV is false in the provided bundle, so there is no source-grounded evidence of active exploitation here.

Researcher notes

Key conditions are vfs_worm enabled, authenticated access, and write permission to the share. The affected list includes duplicates and some unknown or version-unspecified entries. Use Red Hat CVE and RHSA pages as authoritative remediation sources; avoid assuming impact on non-Red Hat distributions from this bundle alone.

Mitigation direction

  • Review Red Hat advisories for the affected platform and apply the relevant Samba or rhcos updates.
  • Identify shares using Samba vfs_worm and confirm business reliance on WORM guarantees.
  • Restrict write access on WORM-protected shares until vendor guidance is applied.
  • For RHEL 6 or unclear cases, check Red Hat support guidance directly.

Validation and detection

  • Inventory Samba package versions against the affected Red Hat product list.
  • Confirm whether vfs_worm is enabled on any Samba share configuration.
  • Review file-retention use cases for audit, legal hold, or compliance dependency.
  • After updating, verify Red Hat advisory status shows the system remediated.
Prepared
Confidence
high
Sources
12

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.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-280: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
description · low confidence lookup

Container behavior lookup

The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-2340 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.5 (3.1)
Known Exploited
No
Published

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

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.

1CVSS vectors
5Timeline events
1ADP providers
14Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
6.5CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N2.83.6redhat

Vulnerability scoring details

Base CVSS 3.1 score

6.5Medium
CVSS 3.1 vector shape for CVE-2026-2340Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. Source timelineredhat

    Reported to Red Hat.

  3. Source timelineredhat

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Red HatRed Hat Enterprise Linux 10samba, 0:4.23.5-109.el10_2affected
Red HatRed Hat Enterprise Linux 10.0 Extended Update Supportsamba, 0:4.21.3-114.el10_0.1affected
Red HatRed Hat Enterprise Linux 8samba, 0:4.19.4-16.el8_10affected
Red HatRed Hat Enterprise Linux 8samba, 0:4.19.4-16.el8_10affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supportsamba, 0:4.15.5-16.el8_6.1affected
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-Onsamba, 0:4.15.5-16.el8_6.1affected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Servicesamba, 0:4.17.5-7.el8_8.1affected
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP Solutionssamba, 0:4.17.5-7.el8_8.1affected
Red HatRed Hat Enterprise Linux 9samba, 0:4.23.5-10.el9_8affected
Red HatRed Hat Enterprise Linux 9samba, 0:4.23.5-10.el9_8affected
Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP Solutionssamba, 0:4.17.5-105.el9_2.5affected
Red HatRed Hat Enterprise Linux 9.4 Update Services for SAP Solutionssamba, 0:4.19.4-105.el9_4.4affected
Red HatRed Hat Enterprise Linux 9.6 Extended Update Supportsamba, 0:4.21.3-14.el9_6.1affected
Red HatRed Hat OpenShift Container Platform 4.19rhcos, 4.19.9.6.202606241344-0affected
Red HatRed Hat Enterprise Linux 6sambaunknown
Red HatRed Hat Enterprise Linux 6samba4unknown
Red HatRed Hat Enterprise Linux 7sambaaffected
Weakness

CWE details

CWE-280

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

CWE-280 · source CWE mapping

Improper Handling of Insufficient Permissions or Privileges

Improper Handling of Insufficient Permissions or Privileges represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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