nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race
When find_or_alloc_open_stateowner() encounters an unconfirmed owner, it
calls release_openowner() and sets oo = NULL. Control then falls through
past the `if (oo)` guard -- which would have freed any pre-allocated
`new` -- and unconditionally executes `new = alloc_stateowner(...)`. If
`new` was already allocated on a prior iteration, the pointer is
silently overwritten and the previous allocation (slab object + owner
name buffer) is leaked.
This requires a race: two NFSv4.0 OPEN threads with the same owner
string, where a concurrent thread inserts a new unconfirmed owner into
the hash between retry iterations. The window is narrow but repeatable
under adversarial conditions.
Fix by adding `goto retry` after `oo = NULL` so the already-allocated
`new` is reused on the next iteration rather than overwritten.
Analysis
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Sun, 19 Jul 2026 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race When find_or_alloc_open_stateowner() encounters an unconfirmed owner, it calls release_openowner() and sets oo = NULL. Control then falls through past the `if (oo)` guard -- which would have freed any pre-allocated `new` -- and unconditionally executes `new = alloc_stateowner(...)`. If `new` was already allocated on a prior iteration, the pointer is silently overwritten and the previous allocation (slab object + owner name buffer) is leaked. This requires a race: two NFSv4.0 OPEN threads with the same owner string, where a concurrent thread inserts a new unconfirmed owner into the hash between retry iterations. The window is narrow but repeatable under adversarial conditions. Fix by adding `goto retry` after `oo = NULL` so the already-allocated `new` is reused on the next iteration rather than overwritten. | |
| Title | nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-07-19T12:01:57.261Z
Reserved: 2026-06-09T07:44:35.402Z
Link: CVE-2026-53394
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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No weakness.