smb: client: split cached_fid bitfields to avoid shared-byte RMW races
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: split cached_fid bitfields to avoid shared-byte RMW races is_open, has_lease and on_list are stored in the same bitfield byte in struct cached_fid but are updated in different code paths that may run concurrently. Bitfield assignments generate byte read–modify–write operations (e.g. `orb $mask, addr` on x86_64), so updating one flag can restore stale values of the others. A possible interleaving is: CPU1: load old byte (has_lease=1, on_list=1) CPU2: clear both flags (store 0) CPU1: RMW store (old | IS_OPEN) -> reintroduces cleared bits To avoid this class of races, convert these flags to separate bool fields.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.1 and later | 6.1.164, 6.6.125, 6.12.72, 6.18.11, 6.19.1, 7.0 | Patch available | CNA |
- Linux VendorLinux Affected 6.1 and later Fixed in 6.1.164, 6.6.125, 6.12.72, 6.18.11, 6.19.1, 7.0 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 6.1 to before 6.1.164; 6.2 to before 6.6.125; 6.7 to before 6.12.72; 6.13 to before 6.18.11; 6.19 to before 6.19.1 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.1 to before 6.1.164; 6.2 to before 6.6.125; 6.7 to before 6.12.72; 6.13 to before 6.18.11; 6.19 to before 6.19.1 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.164, 6.6.125, 6.12.72, 6.18.11, 6.19.1, 7.0
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2026-23230
- 2026-10-03 Alias added: GHSA-p68h-c56f-p3v6
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-16 Priority changed: LOW → MEDIUM
- 2026-10-19 Weakness changed · CISA ADP
- 2026-10-21 Priority changed: MEDIUM → LOW
- 2026-10-25 Priority changed: LOW → MEDIUM
- 2026-10-29 Affected versions changed · Red Hat
References
Patch 6
- https://git.kernel.org/stable/c/569fecc56bfe4df66f05734d67daef887746656b
- https://git.kernel.org/stable/c/4386f6af8aaedd0c5ad6f659b40cadcc8f423828
- https://git.kernel.org/stable/c/3eaa22d688311c708b73f3c68bc6d0c8e3f0f77a
- https://git.kernel.org/stable/c/c4b9edd55987384a1f201d3d07ff71e448d79c1b
- https://git.kernel.org/stable/c/4cfa4c37dcbcfd70866e856200ed8a2894cac578
- https://git.kernel.org/stable/c/ec306600d5ba7148c9dbf8f5a8f1f5c1a044a241
More Linux Kernel vulnerabilities
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- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2026-23230 · CVE Program
- CVE-2026-23230 · NVD
- FIRST EPSS
- GHSA-p68h-c56f-p3v6 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-23230 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences