Vulnerability · Published Oct 15, 2025 · Assigned by redhat
CVE-2025-9640Samba: vfs_streams_xattr uninitialized memory write possible
Medium 4.3
In plain English
A medium-severity security flaw in samba. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.5%top 58.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
A flaw was found in Samba, in the vfs_streams_xattr module, where uninitialized heap memory could be written into alternate data streams. This allows an authenticated user to read residual memory content that may include sensitive data, resulting in an information disclosure vulnerability.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.22 | samba | 4.21.9-r0 | ALPINE-CVE-2025-9640 |
| Alpine:v3.23 | samba | 4.21.9-r0 | ALPINE-CVE-2025-9640 |
| Alpine:v3.24 | samba | 4.21.9-r0 | ALPINE-CVE-2025-9640 |
| Debian:12 | samba | 2:4.17.12+dfsg-0+deb12u3 | DEBIAN-CVE-2025-9640 |
| Debian:13 | samba | 2:4.22.6+dfsg-0+deb13u1 | DEBIAN-CVE-2025-9640 |
| Debian:14 | samba | 2:4.23.2+dfsg-1 | DEBIAN-CVE-2025-9640 |
| Ubuntu:22.04:LTS | samba | 2:4.15.13+dfsg-0ubuntu1.10 | USN-7826-1 |
| Ubuntu:22.04:LTS | samba | 2:4.15.13+dfsg-0ubuntu1.10 | UBUNTU-CVE-2025-9640 |
| Ubuntu:24.04:LTS | samba | 2:4.19.5+dfsg-4ubuntu9.4 | USN-7826-1 |
| Ubuntu:24.04:LTS | samba | 2:4.19.5+dfsg-4ubuntu9.4 | UBUNTU-CVE-2025-9640 |
| Ubuntu:25.10 | samba | 2:4.22.3+dfsg-4ubuntu2.1 | UBUNTU-CVE-2025-9640 |
| Ubuntu:25.10 | samba | 2:4.22.3+dfsg-4ubuntu2.1 | USN-7826-1 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| samba | 0 – before 4.21.94.22.0 – before 4.21.54.23.0 – before 4.23.2 | |
| Red Hat | Red Hat Enterprise Linux 10 | see references |
| Red Hat | Red Hat Enterprise Linux 6 | see references |
| Red Hat | Red Hat Enterprise Linux 6 | see references |
| Red Hat | Red Hat Enterprise Linux 7 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 9 | see references |
| Red Hat | Red Hat OpenShift Container Platform 4 | see references |
| Red Hat | Red Hat OpenShift Container Platform 4 | see references |
Weakness: CWE-908 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
References
- https://access.redhat.com/security/cve/CVE-2025-9640 vdb-entry, x_refsource_REDHAT
- RHBZ#2391698 issue-tracking, x_refsource_REDHAT
- https://www.samba.org/samba/history/security.html
- http://www.openwall.com/lists/oss-security/2025/10/15/2
- http://www.openwall.com/lists/oss-security/2025/10/16/2
- https://lists.debian.org/debian-lts-announce/2025/11/msg00027.html