CVE-2026-2340: A flaw was found in Samba’s vfs_worm module

This month

MEDIUM 6.5WATCHLISTDOWNGRADEDOWNGRADEMITIGATE

CVE-2026-2340 is a medium-severity flaw (CVSS 6.5) affecting openshift container platform, samba, enterprise linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.9% (top 39%)
CISA exploited list	No
Weakness	CWE-280
Published	2026-05-27
Last modified	2026-10-15

Publisher (CNA): Red Hat, Inc. · Vendor: redhat · samba

Last updated 2026-10-15 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-27 14:16 UTCPublished CVE record published
2026-10-15 17:17 UTCUpdated Record last modified

redhat openshift container platform DOWNGRADE

Affected: 4.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.0

1. Check installed version

apt-cache policy openshift-container-platform || rpm -q openshift-container-platform || openshift-container-platform --version

2. No fixed release: DOWNGRADE to a release before 4.0 (Debian / Ubuntu)

apt-cache madison openshift-container-platform sudo apt install openshift-container-platform=<VERSION_BEFORE_4.0> sudo apt-mark hold openshift-container-platform

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openshift-container-platform sudo dnf downgrade openshift-container-platform-<VERSION_BEFORE_4.0> sudo dnf versionlock add openshift-container-platform

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

samba samba DOWNGRADE

Affected: >= 4.1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.1.0

1. Check installed version

apt-cache policy samba || rpm -q samba || samba --version

2. No fixed release: DOWNGRADE to a release before 4.1.0 (Debian / Ubuntu)

apt-cache madison samba sudo apt install samba=<VERSION_BEFORE_4.1.0> sudo apt-mark hold samba

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list samba sudo dnf downgrade samba-<VERSION_BEFORE_4.1.0> sudo dnf versionlock add samba

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

redhat enterprise linux MITIGATE

Affected: 7.0 · 8.0 · 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Advisories and coverage

Official advisories

AlmaLinux Errata: [ALSA-2026:25049] Critical: samba security update 2026-06-11

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-2340?

openshift container platform: downgrade or apply the listed mitigation; samba: downgrade or apply the listed mitigation; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-2340 being exploited?

CVE-2026-2340 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-2340 affect?

CVE-2026-2340 affects openshift container platform, samba, enterprise linux. Severity is medium (CVSS 6.5). 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 oper

How urgent is CVE-2026-2340?

Priority 43/100. On your watchlist

Software pages

Samba vulnerabilities · Red Hat OpenShift vulnerabilities

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References

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