CVE-2026-89742
Description
In the Linux kernel, the following vulnerability has been resolved:
rapidio: mport_cdev: fix use-after-free in dma_req_free()
dma_req_free() acquires buf_mutex through req->map, drops the mapping reference with kref_put(), and then dereferences req->map again to unlock the mutex.
If kref_put() drops the last reference, mport_release_mapping() frees the mapping, and the subsequent mutex_unlock() dereferences a freed object. This is a use-after-free.
Fix this by caching map and md before kref_put(), clearing req->map while holding buf_mutex, and using the cached md for mutex unlocking.
The bug is reachable from userspace via the RapidIO mport character device interface.
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LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
3- osv-coords2 versions
>= 4.6.0, < 5.10.270+ 1 more
- (no CPE)range: >= 4.6.0, < 5.10.270
- (no CPE)range: < 7.2.7-1.1
Patches
Vulnerability mechanics
References
8- git.kernel.org/stable/c/00c5ed913b0dc563fbeb8a97ea8916c03bbbbf6anvd
- git.kernel.org/stable/c/211c68d817a3d9dc14c0026a59da7cac30f8147envd
- git.kernel.org/stable/c/26ccfe7d69e27b0d933ae0a64a23a0cb9b9a85a6nvd
- git.kernel.org/stable/c/5cbef379a94b161726c5f504598bf4791d45cedcnvd
- git.kernel.org/stable/c/9a9929ec875ff20922c90c96fd544ae8a2a61a8dnvd
- git.kernel.org/stable/c/bd8881c24a9520f9c3d3e855d866197f63e471a7nvd
- git.kernel.org/stable/c/e6e925cc1f8067c65c7bec3da50a0ead3b3ef4e0nvd
- git.kernel.org/stable/c/fc79c07cdcde02c5b17633d78777de6ac2c14b29nvd
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