cbcvebase.
CVE-2026-31584
published 2026-04-24

CVE-2026-31584: In the Linux kernel, the following vulnerability has been resolved: media: mediatek: vcodec: fix use-after-free in encoder release path The…

PriorityP340high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.13%
2.6th percentile
In the Linux kernel, the following vulnerability has been resolved: media: mediatek: vcodec: fix use-after-free in encoder release path The fops_vcodec_release() function frees the context structure (ctx) without first cancelling any pending or running work in ctx->encode_work. This creates a race window where the workqueue handler (mtk_venc_worker) may still be accessing the context memory after it has been freed. Race condition: CPU 0 (release path) CPU 1 (workqueue) --------------------- ------------------ fops_vcodec_release() v4l2_m2m_ctx_release() v4l2_m2m_cancel_job() // waits for m2m job "done" mtk_venc_worker() v4l2_m2m_job_finish() // m2m job "done" // BUT worker still running! // post-job_finish access: other ctx dereferences // UAF if ctx already freed // returns (job "done") kfree(ctx) // ctx freed Root cause: The v4l2_m2m_ctx_release() only waits for the m2m job lifecycle (via TRANS_RUNNING flag), not the workqueue lifecycle. After v4l2_m2m_job_finish() is called, the m2m framework considers the job complete and v4l2_m2m_ctx_release() returns, but the worker function continues executing and may still access ctx. The work is queued during encode operations via: queue_work(ctx->dev->encode_workqueue, &ctx->encode_work) The worker function accesses ctx->m2m_ctx, ctx->dev, and other ctx fields even after calling v4l2_m2m_job_finish(). This vulnerability was confirmed with KASAN by running an instrumented test module that widens the post-job_finish race window. KASAN detected: BUG: KASAN: slab-use-after-free in mtk_venc_worker+0x159/0x180 Read of size 4 at addr ffff88800326e000 by task kworker/u8:0/12 Workqueue: mtk_vcodec_enc_wq mtk_venc_worker Allocated by task 47: __kasan_kmalloc+0x7f/0x90 fops_vcodec_open+0x85/0x1a0 Freed by task 47: __kasan_slab_free+0x43/0x70 kfree+0xee/0x3a0 fops_vcodec_release+0xb7/0x190 Fix this by calling cancel_work_sync(&ctx->encode_work) before kfree(ctx). This ensures the workqueue handler is both cancelled (if pen

Affected

38 ranges· showing 25
VendorProductVersion rangeFixed in
linuxlinux
linuxlinux>= 0934d37596151edce115c6d0843a9ad7d5e5d232 < 9a9bdaf9dc42ccca50e53f82165292f74a365c119a9bdaf9dc42ccca50e53f82165292f74a365c11
linuxlinux>= 0934d37596151edce115c6d0843a9ad7d5e5d232 < a8a55913552aed45108525d1851c65e1db0cc25ba8a55913552aed45108525d1851c65e1db0cc25b
linuxlinux>= 0934d37596151edce115c6d0843a9ad7d5e5d232 < f99353cd0e9f58bf17889049137b8d65fb44ebf1f99353cd0e9f58bf17889049137b8d65fb44ebf1
linuxlinux>= 0934d37596151edce115c6d0843a9ad7d5e5d232 < 93d9a58961a9e09306857e999b3ee76aa4be67f093d9a58961a9e09306857e999b3ee76aa4be67f0
linuxlinux>= 0934d37596151edce115c6d0843a9ad7d5e5d232 < f1692337c6fa26e04f89b22a4d84bf5b7ada50d1f1692337c6fa26e04f89b22a4d84bf5b7ada50d1
linuxlinux>= 0934d37596151edce115c6d0843a9ad7d5e5d232 < 76e35091ffc722ba39b303e48bc5d08abb59dd5676e35091ffc722ba39b303e48bc5d08abb59dd56
linuxlinux_kernel< 6.6.1366.6.136
linuxlinux_kernel>= 6.12 < 6.12.836.12.83
linuxlinux_kernel>= 6.13 < 6.18.246.18.24
linuxlinux_kernel>= 6.19 < 6.19.146.19.14
linuxlinux_kernel>= 7.0 < 7.0.17.0.1
ubuntulinux
ubuntulinux-aws
ubuntulinux-azure
ubuntulinux-azure-6.8
ubuntulinux-azure-fde
ubuntulinux-azure-fde-6.8
ubuntulinux-azure-fips
ubuntulinux-fips
ubuntulinux-gcp
ubuntulinux-gcp-6.8
ubuntulinux-gcp-fips
ubuntulinux-gke
ubuntulinux-gkeop

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vendor_ubuntu2.0LOW
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