Description
In the Linux kernel, the following vulnerability has been resolved:
smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()
cifs_posix_to_fattr() ignores the return value of posix_info_parse().
When a malformed POSIX directory entry is encountered (e.g. invalid
SID lengths from an untrusted server), posix_info_parse() returns -1
without populating the 'parsed' struct. The uninitialized stack
memory in parsed.owner and parsed.group is then passed to
sid_to_id(), which processes the garbage bytes and passes them to
request_key() to construct a SID string, potentially leaking kernel
stack contents to the userspace idmap daemon.
Fix this by checking the return value and skipping the SID-to-id
mapping when parsing fails. The remaining fattr fields (timestamps,
mode, etc.) are populated directly from the 'info' pointer so they
are unaffected.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.8.17 – < 5.9, 5.9.2 – < 5.10, 5.10 | 5.9 |
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 | 7.2.7-1 | — |
| Debian 13 | linux | 6.12.115-2 | — |
| Debian 12 | linux | No fix yet | — |
| Debian 12 | linux-6.12 | 6.12.115-2~deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | No fix yet | — |
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | No fix yet | — |
| Ubuntu 26.04 LTS | linux | 7.0.0-42.42 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-aws | 7.0.0-1016.17 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-azure | 7.0.0-1020.21 | USN-9019-1 |
| Ubuntu 26.04 LTS | linux-azure-fde | 7.0.0-1019.19 | USN-9020-1 |
| Ubuntu 26.04 LTS | linux-gcp | 7.0.0-1016.18 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-gke | 7.0.0-1010.11 | USN-9020-1 |
| Ubuntu 26.04 LTS | linux-ibm +1 | 7.0.0-1017.17 | USN-8960-1, USN-8959-1 |
| Ubuntu 26.04 LTS | linux-nvidia +1 | No fix yet | — |
| Ubuntu 26.04 LTS | linux-oracle | 7.0.0-1015.16 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-raspi | 7.0.0-1023.23 | USN-9021-1 |
| Ubuntu 26.04 LTS | linux-realtime | 7.0.0-43.43.1 | USN-9020-1 |
| Ubuntu 26.04 LTS | linux-riscv | 7.0.0-42.42.1 | — |
| Ubuntu 24.04 LTS | linux +46 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-aws-7.0 | 7.0.0-1017.18~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-azure-fde-7.0 | 7.0.0-1019.19~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-gcp-7.0 | 7.0.0-1017.19~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-hwe-7.0 | 7.0.0-42.42~24.04.1 | USN-8959-1 |
| Ubuntu 24.04 LTS | linux-oracle-7.0 | 7.0.0-1016.18~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-riscv-7.0 | 7.0.0-42.42.1~24.04.1 | — |
| Ubuntu 22.04 LTS | linux +59 | No fix yet | — |
Show 18 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| 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-realtime +3 | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime +2 | No fix yet | — |
| Ubuntu Pro FIPS 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux +21 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | linux +12 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | linux +7 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | linux +3 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | kernel-64kb +8 | 6.12.0-160000.40.1 | SUSE-SU-2026:24446-1 |
| SLES for SAP 16.0 | kernel-default-base | 6.12.0-160000.40.1.160000.2.29 | SUSE-SU-2026:24446-1 |
| SLES 16.0 | kernel-64kb +8 | 6.12.0-160000.40.1 | SUSE-SU-2026:24446-1, SUSE-SU-2026:24437-1 |
| SLES 16.0 | kernel-default-base | 6.12.0-160000.40.1.160000.2.29 | SUSE-SU-2026:24446-1 |
| SLE Micro 6.2 | kernel-default-base | 6.12.0-160000.40.1.160000.2.29 | SUSE-SU-2026:24422-1 |
| SLE Micro 6.2 | kernel-rt +5 | 6.12.0-160000.40.1 | SUSE-SU-2026:24422-1, SUSE-SU-2026:24386-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 6.1 | kernel-default-base | 6.4.0-159998.55.1.159998.21.41 | SUSE-SU-2026:24619-1 |
| SLE Micro 6.1 | kernel-source +2 | 6.4.0-159998.55.1 | SUSE-SU-2026:24619-1 |
| SLE Micro 6.0 | kernel-default-base | 6.4.0-159998.55.1.159998.21.42 | SUSE-SU-2026:24550-1 |
| SLE Micro 6.0 | kernel-source +2 | 6.4.0-159998.55.1 | SUSE-SU-2026:24550-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | kernel-source | 7.2.9-1.1 | openSUSE-SU-2026:12074-1 |
| openSUSE Leap 16.0 | kernel-default-base | 6.12.0-160000.40.1.160000.2.29 | openSUSE-SU-2026:22167-1 |
| openSUSE Leap 16.0 | kernel-rt +11 | 6.12.0-160000.40.1 | openSUSE-SU-2026:22167-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.12.114-139.210 | 1:1.0-0.amzn2023 | ALAS2023-2026-3402 |
| Amazon Linux 2023 | perf6.12 +11 | 1:6.12.114-139.210.amzn2023 | ALAS2023-2026-3402 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | kernel | 6.6.161.1-1 | — |
Advisories 15
- USN-9021-1 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- WID-SEC-2026-3579 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- USN-9020-1 linux-aws-7.0, linux-azure-fde, linux-azure-fde-7.0, linux-gcp-7.0, linux-gke, linux-oracle-7.0, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8959-1 linux, linux-aws, linux-gcp, linux-hwe-7.0, linux-ibm, linux-oracle vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- SUSE-SU-2026:24619-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Nov 12, 2026
- USN-9019-1 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8960-1 linux-oem-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- ALAS2023-2026-3402 Important: kernel6.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Nov 11, 2026
- SUSE-SU-2026:24550-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Nov 6, 2026
- SUSE-SU-2026:24437-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Nov 1, 2026
- SUSE-SU-2026:24446-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Nov 1, 2026
- SUSE-SU-2026:24422-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 30, 2026
- SUSE-SU-2026:24386-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 30, 2026
- openSUSE-SU-2026:22167-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 25, 2026
- openSUSE-SU-2026:12074-1 kernel-devel-7.2.9-1.1 on GA media SUSE / openSUSE Security Updates · Oct 9, 2026
References
- https://git.kernel.org/stable/c/1915b69e36906968e2b698699d0f219875ae846e
- https://git.kernel.org/stable/c/604feb3e8141bf11f5afd48d36d401fee5af9536
- https://git.kernel.org/stable/c/33106019c3be57b5fc6411cfaad6d98214a51265
- https://git.kernel.org/stable/c/2be31f252ade791b84f7164991f14436aed1d4b9
- https://git.kernel.org/stable/c/c9a8b60ce140a68d172452f418137fc7ddbae7db
- https://git.kernel.org/stable/c/da6e25842431982d5a53cf00d925b98c690f4467