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.

Published: 2026-05-27 Last update: 2026-06-04 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-2340 is rated Low Risk (33.1/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.07%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-2340

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-04 0.03% 0.07% +0.04%
2 2026-05-28 — 0.03% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-2340

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]

Weakness enumeration for CVE-2026-2340

GitHub Security Advisory for CVE-2026-2340

GHSA-m6w2-p258-gxqp · Severity: medium — A flaw was found in Samba’s vfs_worm module. The module is intended to provide write-once, read...

OS Trackers for CVE-2026-2340

vendor priority summary link
debian not yet assigned CVE-2026-2340 not yet assigned priority: Debian including 1 source packages (samba), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2026-2340
redhat medium — https://access.redhat.com/security/cve/CVE-2026-2340
suse medium CVE-2026-2340 severity moderate: SUSE including 172 source package names (ctdb-4.15.13+git.701.449cb7f5cd3-3.106.1, ctdb-4.15.13+git.780.d2f53cbcded-150300.3.103.1, …), 468 product×package rows across 29 product lines (SUSE Enterprise Storage 7.1, SUSE Linux Enterprise High Availability Extension 12 SP5, … (29 product lines)): Fixed 271, First Fixed 197. https://www.suse.com/security/cve/CVE-2026-2340/
ubuntu medium CVE-2026-2340 medium priority: Ubuntu including 1 source packages (samba), 9 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): released 5, needs-triage 4. https://ubuntu.com/security/CVE-2026-2340

Affected software / configurations for CVE-2026-2340

Vendor Product Version Raw CPE
redhat openshift_container_platform 4.0 cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
samba samba >= 4.1.0 cpe:2.3:a:samba:samba:*:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
redhat enterprise_linux 10.0 cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*

References for CVE-2026-2340

cvelogic Threat Intelligence