Skip to content

VulnTideExploited vulnerabilities, by vendor. Data as of 29 Oct 2026.

Not in CISA KEVPublished 27 May 2026CVSS 6.5 mediumEPSS 0.9% probability of exploitation in 30 daysFound by AI: AISLE

Red Hat

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

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.9%

EPSS score, percentile 60.8 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

6.5 Medium

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (12)

Which versions are affected?

Unaffected 0:4.23.5-109.el10_2; 0:4.21.3-114.el10_0.1; 0:4.19.4-16.el8_10; 0:4.19.4-16.el8_10; 0:4.15.5-16.el8_6.1; 0:4.15.5-16.el8_6.1; and 14 more

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Workaround (from the CVE record)

Administrators can mitigate this issue by: Setting read-only permissions on protected files at the underlying filesystem level will prevent modifications. Configuring ```worm:grace_period = 0``` (zero or less) in smb.conf will eliminate the writable grace period (will eliminate the window in which the rename can happen), understanding that this may impact workflows requiring multi-step file creation.

Advisories and patches

RHSA-2026:22644 (Vendor advisory)
RHSA-2026:22963 (Vendor advisory)
RHSA-2026:25049 (Vendor advisory)
RHSA-2026:25979 (Vendor advisory)
RHSA-2026:28053 (Vendor advisory)
RHSA-2026:28054 (Vendor advisory)
RHSA-2026:28055 (Vendor advisory)
RHSA-2026:28056 (Vendor advisory)
RHSA-2026:28057 (Vendor advisory)
RHSA-2026:29863 (Vendor advisory)
RHSA-2026:56786 (Vendor advisory)
RHSA-2026:56853 (Vendor advisory)

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Red Hat Red Hat Enterprise Linux 10
Status	Versions
Unaffected	0:4.23.5-109.el10_2

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
Status	Versions
Unaffected	0:4.21.3-114.el10_0.1

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 8
Status	Versions
Unaffected	0:4.19.4-16.el8_10

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 8
Status	Versions
Unaffected	0:4.19.4-16.el8_10

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
Status	Versions
Unaffected	0:4.15.5-16.el8_6.1

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
Status	Versions
Unaffected	0:4.15.5-16.el8_6.1

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
Status	Versions
Unaffected	0:4.17.5-7.el8_8.1

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
Status	Versions
Unaffected	0:4.17.5-7.el8_8.1

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 9
Status	Versions
Unaffected	0:4.23.5-10.el9_8

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 9
Status	Versions
Unaffected	0:4.23.5-10.el9_8

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
Status	Versions
Unaffected	0:4.17.5-105.el9_2.5

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
Status	Versions
Unaffected	0:4.19.4-105.el9_4.4

Versions not listed are: affected.

Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support
Status	Versions
Unaffected	0:4.21.3-14.el9_6.1

Versions not listed are: affected.

Red Hat Red Hat OpenShift Container Platform 4.12
Status	Versions
Unaffected	412.86.202608241157-0

Versions not listed are: affected.

Red Hat Red Hat OpenShift Container Platform 4.12
Status	Versions
Unaffected	412.86.202609082051-0

Versions not listed are: affected.

Red Hat Red Hat OpenShift Container Platform 4.13
Status	Versions
Unaffected	413.92.202609080414-0

Versions not listed are: affected.

Red Hat Red Hat OpenShift Container Platform 4.13
Status	Versions
Unaffected	413.92.202609302032-0

Versions not listed are: affected.

Red Hat Red Hat OpenShift Container Platform 4.14
Status	Versions
Unaffected	414.92.202608172040-0

Versions not listed are: affected.

Red Hat Red Hat OpenShift Container Platform 4.14
Status	Versions
Unaffected	414.92.202609011250-0

Versions not listed are: affected.

Red Hat Red Hat OpenShift Container Platform 4.15
Status	Versions
Unaffected	415.92.202608180329-0

Versions not listed are: affected.

Versions the record lists as unaffected: 0:4.23.5-109.el10_2, 0:4.21.3-114.el10_0.1, 0:4.19.4-16.el8_10, 0:4.15.5-16.el8_6.1, 0:4.17.5-7.el8_8.1, 0:4.23.5-10.el9_8, 0:4.17.5-105.el9_2.5, 0:4.19.4-105.el9_4.4.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

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 f…

Summary: CVE record, as of 29 Oct 2026.

CISA has not added CVE-2026-2340 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
The CVE record was published on 27 May 2026.
The CVE record carries a CVSS v3.1 base score of 6.5 (Medium), given by its CNA.
FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.9% (percentile 60.8), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
The credits in the CVE record name AISLE as finder.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

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.

Source: CVE List, as of 29 Oct 2026. About the data.

Weakness

CWE-280

CWE-280

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

Date	Event
27 May 2026	CVE record published
15 Oct 2026	CVE record last updated

References

15

15 more in the CVE record.

Known exploited Red Hat vulnerabilities

CVE-2015-3246: Red Hat Libuser Race Condition Vulnerability (added 26 Aug 2026)
CVE-2015-5287: Red Hat Automatic Bug Reporting Tool Privilege Escalation Vulnerability (added 26 Aug 2026)
CVE-2018-14667: Red Hat JBoss RichFaces Framework Expression Language Injection Vulnerability (added 28 Sep 2023)
CVE-2021-3560: Red Hat Polkit Incorrect Authorization Vulnerability (added 12 May 2023)
CVE-2021-4034: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability (added 27 Jun 2022)