CVE-2026-53161

What it is

In the Linux kernel, the following vulnerability has been resolved: misc: fastrpc: fix use-after-free of fastrpc_user in workqueue context There is a race between fastrpc_device_release() and the workqueue that processes DSP responses. When the user closes the file descriptor, fastrpc_device_release() frees the fastrpc_user structure. Concurrently, an in-flight DSP invocation can complete and fastrpc_rpmsg_callback() schedules context cleanup via schedule_work(&ctx->put_work). If the workqueue runs fastrpc_context_free() in parallel with or after fastrpc_device_release() has freed the user structure, it dereferences the freed fastrpc_user. Depending on the state of the context at the time of the race, any one of the following accesses can be hit: 1. fastrpc_buf_free() calls fastrpc_ipa_to_dma_addr(buf->fl->cctx, ...) to strip the SID bits from the stored IOVA before passing the physical address to dma_free_coherent(). 2. fastrpc_free_map() reads map->fl->cctx->vmperms[0].vmid to reconstruct the source permission bitmask needed for the qcom_scm_assign_mem() call that returns memory from the DSP VM back to HLOS. 3. fastrpc_free_map() acquires map->fl->lock to safely remove the map node from the fl->maps list. The resulting use-after-free manifests as: pc : fastrpc_buf_free+0x38/0x80 [fastrpc] lr : fastrpc_context_free+0xa8/0x1b0 [fastrpc] fastrpc_context_free+0xa8/0x1b0 [fastrpc] fastrpc_context_put_wq+0x78/0xa0 [fastrpc] process_one_work+0x180/0x450 worker_thread+0x26c/0x388 Add kref-based reference counting to fastrpc_user. Have each invoke context take a reference on the user at allocation time and release it when the context is freed. Release the initial reference in fastrpc_device_release() at file close. Move the teardown of the user structure — freeing pending contexts, maps, mmaps, and the channel context reference — into the kref release callback fastrpc_user_free(), so that it runs only when the last reference is dropped, regardless of whether that happens at device close or after the final in-flight context completes.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-06-25 09:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-07-06 16:42 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.1% in the next 30 days (EPSS).
• Severity: 7.8 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-06-25 09:16 UTC

Last modified

2026-07-06 16:42 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-416 · Use after free

Record status

Analyzed

Affected

• Linux Kernel < 5.10.259
• Linux Kernel < 5.15.210
• Linux Kernel < 6.1.176
• Linux Kernel < 6.6.143
• Linux Kernel < 6.12.94
• Linux Kernel < 6.18.36
• Linux Kernel < 7.0.13
• Linux Kernel 7.1

Attack profile CVSS 3.1 · 7.8

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

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