Description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free in session logoff
The sess->user object can currently be in use by another thread, for
example if another connection has sent a session setup request to
bind to the session being free'd. The handler for that connection could
be in the smb2_sess_setup function which makes use of sess->user.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.15 | 6.1.159 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 6.12.29-1 | — |
| Debian 13 | linux | 6.12.29-1 | — |
| Debian 12 | linux | 6.1.159-1 | — |
| Debian 11 | linux-6.1 | 6.1.159-1~deb11u1 | DLA-4436-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | 6.8.0-1017.21 | — |
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | No fix yet | — |
| Ubuntu 25.10 | linux-azure-fde | No fix yet | — |
| Ubuntu 25.04 | linux | 6.14.0-24.24 | USN-7649-1 |
| Ubuntu 25.04 | linux-aws +2 | 6.14.0-1009.9 | USN-7665-1, USN-7649-2, USN-7649-1 |
| Ubuntu 25.04 | linux-azure | 6.14.0-1010.10 | USN-7721-1 |
| Ubuntu 25.04 | linux-gcp | 6.14.0-1011.11 | USN-7649-1 |
| Ubuntu 25.04 | linux-realtime | 6.14.0-1006.6 | USN-7649-1 |
| Ubuntu 24.04 LTS | linux | 6.8.0-101.101 | USN-8059-1 |
| Ubuntu 24.04 LTS | linux-aws +1 | 6.8.0-1047.50 | USN-8059-8, USN-8059-6 |
| Ubuntu 24.04 LTS | linux-aws-6.14 +1 | 6.14.0-1009.9~24.04.1 | USN-7665-2 |
| Ubuntu 24.04 LTS | linux-azure | 6.8.0-1051.57 | USN-8125-1 |
| Ubuntu 24.04 LTS | linux-azure-fde | 6.8.0-1058.65 | — |
| Ubuntu 24.04 LTS | linux-azure-nvidia | 6.8.0-1039.42 | — |
| Ubuntu 24.04 LTS | linux-gcp | 6.8.0-1048.51 | USN-8059-3 |
| Ubuntu 24.04 LTS | linux-gcp-6.14 | 6.14.0-1011.11~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1044.49 | USN-8059-3 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1031.34 | USN-8059-1 |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1045.45 | USN-8059-6 |
| Ubuntu 24.04 LTS | linux-intel +10 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-lowlatency | 6.8.0-101.101.1 | USN-8059-1 |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1047.50.1 | USN-8059-8 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1020.20 | — |
| Ubuntu 24.04 LTS | linux-oem-6.14 | 6.14.0-1007.7 | USN-7650-1 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1044.45 | USN-8059-1 |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1048.52 | USN-8059-1 |
| Ubuntu 24.04 LTS | linux-riscv-6.14 | 6.14.0-24.24.1~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-xilinx | 6.8.0-1024.25 | USN-8059-6 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | linux +49 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-aws-6.8 +1 | 6.8.0-1047.50~22.04.1 | USN-8059-8, USN-8059-6 |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1051.57~22.04.1 | USN-8126-1 |
| Ubuntu 22.04 LTS | linux-azure-fde-6.8 | 6.8.0-1058.65~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1048.51~22.04.1 | USN-8059-3 |
| Ubuntu 22.04 LTS | linux-hwe-6.8 +1 | 6.8.0-101.101~22.04.1 | USN-8059-1 |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1045.45~22.04.1 | USN-8059-6 |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-101.101.1~22.04.1 | USN-8059-1 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1044.45~22.04.1 | USN-8059-3 |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2038.39 | USN-8059-2 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1042.43 | USN-8059-4 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 | 6.14.0-1010.10~24.04.1 | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime +1 | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1042.43~22.04.1 | USN-8059-4 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-aws-fips | 6.8.0-1047.50+fips1 | USN-8059-7 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-azure-fips | 6.8.0-1047.53+fips1 | USN-8059-9 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-101.101+fips1 | USN-8059-5 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-gcp-fips | 6.8.0-1048.51+fips1 | USN-8059-5 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux-aws-5.15 +10 | No fix yet | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-101.33.4.3.el10uek | ELSA-2025-20530, ELSA-2025-20480 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 3 repositories
-
SeanHeelan/o3_finds_cve-2025-37899 ★ 353 · May 22, 2025
Artefacts for blog post on finding CVE-2025-37899 with o3
-
ccss17/o3_finds_cve-2025-37899 ★ 0 · Sep 11, 2025
Artefacts for blog post on finding CVE-2025-37899 with o3
-
vett3x/SMB-LINUX-CVE-2025-37899 ★ 0 · Jun 9, 2025
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 21
- WID-SEC-2025-1114 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- USN-8126-1 linux-azure-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8125-1 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7650-1 linux-oem-6.14 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-7665-2 linux-aws-6.14 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8059-1 linux, linux-gkeop, linux-hwe-6.8, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-oracle, linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-8059-9 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-8059-5 linux-fips, linux-gcp-fips vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-8059-6 linux-aws, linux-aws-6.8, linux-ibm, linux-ibm-6.8, linux-xilinx vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-8059-2 linux-raspi-realtime vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-8059-3 linux-gcp, linux-gcp-6.8, linux-gke, linux-oracle-6.8 vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-8059-4 linux-realtime, linux-realtime-6.8 vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-8059-8 linux-nvidia, linux-nvidia-6.8, linux-nvidia-lowlatency vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-8059-7 linux-aws-fips vulnerabilities Ubuntu Security Notices (USN) · Oct 27, 2026
- USN-7665-1 linux-oracle vulnerabilities Ubuntu Security Notices (USN) · Feb 4, 2026
- USN-7649-2 linux-aws vulnerabilities Ubuntu Security Notices (USN) · Feb 4, 2026
- USN-7721-1 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Feb 4, 2026
- USN-7649-1 linux, linux-gcp, linux-raspi, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Feb 4, 2026
- DLA-4436-1 linux-6.1 - security update Debian Security (DSA / DLA) · Jan 14, 2026
- ELSA-2025-20530 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Aug 18, 2025
- ELSA-2025-20480 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jul 17, 2025
References
- https://git.kernel.org/stable/c/931dc8a3670f71c45c0b1379ea4e92dafbda1aca
- https://git.kernel.org/stable/c/70ad6455139e26e85f48f95d0e21f351c1909342
- https://git.kernel.org/stable/c/d5ec1d79509b3ee01de02c236f096bc050221b7f
- https://git.kernel.org/stable/c/02d16046cd11a5c037b28c12ffb818c56dd3ef43
- https://git.kernel.org/stable/c/2fc9feff45d92a92cd5f96487655d5be23fb7e2b