CVE-2025-40285 json
smb/server: fix possible refcount leak in smb2_sess_setup()
published 2025-12-06 11 mo ago modified 2026-10-15 24 d ago also EUVD-2025-201570
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 38%
- public exploits
- 0
- none known
Summary
In the Linux kernel, the following vulnerability has been resolved:
smb/server: fix possible refcount leak in smb2_sess_setup()
Reference count of ksmbd_session will leak when session need reconnect. Fix this by adding the missing ksmbd_user_session_put().
Patch / fix
- Linux Linux 5.16, 6.1.159, 6.6.117, 6.12.59, 6.17.9, 6.18
- linux Debian 12 6.1.159-1
- linux Debian 13 6.12.63-1
- linux Debian 14 6.17.9-1
debian advisories DEBIAN-CVE-2025-40285
- linux Ubuntu 24.04 LTS 6.8.0-106.106
- linux Ubuntu 25.10 6.17.0-14.14
- linux-aws Ubuntu 24.04 LTS 6.8.0-1050.53
- linux-aws Ubuntu 25.10 6.17.0-1007.7
- linux-gcp Ubuntu 24.04 LTS 6.8.0-1052.55
- linux-gcp Ubuntu 25.10 6.17.0-1007.7
- linux-gke Ubuntu 24.04 LTS 6.8.0-1048.53
- linux-ibm Ubuntu 24.04 LTS 6.8.0-1049.49
ubuntu advisories UBUNTU-CVE-2025-40285
Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
- git.kernel.org/stable/c/6fc935f798d44a8eb8a5e6659198399fbf57b981 commit
- git.kernel.org/stable/c/e671f9bb97805771380c98de944e2ceab6949188 commit
- git.kernel.org/stable/c/dcc51dfe6ff26b52cac106865a172ac982d78401 commit
- git.kernel.org/stable/c/d37b2c81c83d6c0d5ca582f4fe73c672983f9e0d commit
- git.kernel.org/stable/c/379510a815cb2e64eb0a379cb62295d6ade65df0 commit
Vendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2025-40285 updated
kernel: smb/server: fix possible refcount leak in smb2_sess_setup()
-
Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernelnot affected: vulnerable code not present
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
Exploit prediction
0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected products
- Linux Linux
Classification
- Technology feeds
References
- git.kernel.org /stable/c/6fc935f798d44a8eb8a5e6659198399fbf57b981
- git.kernel.org /stable/c/e671f9bb97805771380c98de944e2ceab6949188
- git.kernel.org /stable/c/dcc51dfe6ff26b52cac106865a172ac982d78401
- git.kernel.org /stable/c/d37b2c81c83d6c0d5ca582f4fe73c672983f9e0d
- git.kernel.org /stable/c/379510a815cb2e64eb0a379cb62295d6ade65df0
Sources
- CVE List CVE-2025-40285
- NVD CVE-2025-40285
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