CVE-2026-23230

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxebe98f1447bbccf8228335c62d86af02a0ed23f7 < 569fecc56bfe4df66f05734d67daef887746656baffected
LinuxLinuxebe98f1447bbccf8228335c62d86af02a0ed23f7 < 4386f6af8aaedd0c5ad6f659b40cadcc8f423828affected
LinuxLinuxebe98f1447bbccf8228335c62d86af02a0ed23f7 < 3eaa22d688311c708b73f3c68bc6d0c8e3f0f77aaffected
LinuxLinuxebe98f1447bbccf8228335c62d86af02a0ed23f7 < c4b9edd55987384a1f201d3d07ff71e448d79c1baffected
LinuxLinuxebe98f1447bbccf8228335c62d86af02a0ed23f7 < 4cfa4c37dcbcfd70866e856200ed8a2894cac578affected
LinuxLinuxebe98f1447bbccf8228335c62d86af02a0ed23f7 < ec306600d5ba7148c9dbf8f5a8f1f5c1a044a241affected
LinuxLinux6.1affected
LinuxLinux0 < 6.1unaffected
LinuxLinux6.1.164 <= 6.1.*unaffected
LinuxLinux6.6.125 <= 6.6.*unaffected
LinuxLinux6.12.72 <= 6.12.*unaffected
LinuxLinux6.18.11 <= 6.18.*unaffected
LinuxLinux6.19.1 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

ADP Enrichment

Additional References

References