{ "cveId": "CVE-2026-31584", "url": "https://patchblox.com/security/cve/CVE-2026-31584", "summary": "CVE-2026-31584 is fixed in 14 products on 1 platform, first by DEBIAN-CVE-2026-31584, released May 15, 2026. It is not reported as exploited. Patch Radar priority: High.", "title": "media: mediatek: vcodec: fix use-after-free in encoder release path", "description": "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-\u003Eencode_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 \u0022done\u0022 mtk_venc_worker() v4l2_m2m_job_finish() // m2m job \u0022done\u0022 // BUT worker still running! // post-job_finish access: other ctx dereferences // UAF if ctx already freed // returns (job \u0022done\u0022) 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-\u003Edev-\u003Eencode_workqueue, \u0026ctx-\u003Eencode_work) The worker function accesses ctx-\u003Em2m_ctx, ctx-\u003Edev, 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\u002B0x159/0x180 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\u002B0x7f/0x90 fops_vcodec_open\u002B0x85/0x1a0 Freed by task 47: __kasan_slab_free\u002B0x43/0x70 kfree\u002B0xee/0x3a0 fops_vcodec_release\u002B0xb7/0x190 Fix this by calling cancel_work_sync(\u0026ctx-\u003Eencode_work) before kfree(ctx). This ensures the workqueue handler is both cancelled (if pending) and synchronized (waits for any running handler to complete) before the context is freed. Placement rationale: The fix is placed after v4l2_ctrl_handler_free() and before list_del_init(\u0026ctx-\u003Elist). At this point, all m2m operations are done (v4l2_m2m_ctx_release() has returned), and we need to ensure the workqueue is synchronized before removing ctx from the list and freeing it. Note: The open error path does NOT need cancel_work_sync() because INIT_WORK() only initializes the work structure - it does not schedule it. Work is only scheduled later during device_run() operations.", "published": "2026-04-24T15:16:33Z", "severity": "Important", "cvss": 7.8, "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "epss": 0.00126, "epssPercentile": 0.02273, "priority": "High", "priorityTier": 3, "exploited": false, "vendorExploited": false, "disclosed": false, "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-31584", "fixes": [ { "platform": "linux", "product": "dtb-aarch64", "release": "opensuse-leap 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "OPENSUSE-SU-2026:20965-1", "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-20965-1", "released": "2026-06-15T13:44:30Z" }, { "platform": "linux", "product": "kernel-64kb", "release": "opensuse-leap 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "OPENSUSE-SU-2026:20965-1", "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-20965-1", "released": "2026-06-15T13:44:30Z" }, { "platform": "linux", "product": "kernel-64kb", "release": "sles 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "SUSE-SU-2026:22127-1", "url": "https://patchblox.com/security/fix/linux/suse-su-2026-22127-1", "released": "2026-06-15T13:06:19Z" }, { "platform": "linux", "product": "kernel-azure", "release": "opensuse-leap 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "OPENSUSE-SU-2026:20965-1", "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-20965-1", "released": "2026-06-15T13:44:30Z" }, { "platform": "linux", "product": "kernel-azure", "release": "sles 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "SUSE-SU-2026:22127-1", "url": "https://patchblox.com/security/fix/linux/suse-su-2026-22127-1", "released": "2026-06-15T13:06:19Z" }, { "platform": "linux", "product": "kernel-default", "release": "opensuse-leap 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "OPENSUSE-SU-2026:20965-1", "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-20965-1", "released": "2026-06-15T13:44:30Z" }, { "platform": "linux", "product": "kernel-default", "release": "sles 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "SUSE-SU-2026:22127-1", "url": "https://patchblox.com/security/fix/linux/suse-su-2026-22127-1", "released": "2026-06-15T13:06:19Z" }, { "platform": "linux", "product": "kernel-default-base", "release": "opensuse-leap 16.0", "fixedVersion": "6.12.0-160000.35.1.160000.2.16", "fix": "OPENSUSE-SU-2026:20965-1", "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-20965-1", "released": "2026-06-15T13:44:30Z" }, { "platform": "linux", "product": "kernel-default-base", "release": "sles 16.0", "fixedVersion": "6.12.0-160000.35.1.160000.2.16", "fix": "SUSE-SU-2026:22127-1", "url": "https://patchblox.com/security/fix/linux/suse-su-2026-22127-1", "released": "2026-06-15T13:06:19Z" }, { "platform": "linux", "product": "kernel-docs", "release": "opensuse-leap 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "OPENSUSE-SU-2026:20965-1", "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-20965-1", "released": "2026-06-15T13:44:30Z" }, { "platform": "linux", "product": "kernel-docs", "release": "sles 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "SUSE-SU-2026:22127-1", "url": "https://patchblox.com/security/fix/linux/suse-su-2026-22127-1", "released": "2026-06-15T13:06:19Z" }, { "platform": "linux", "product": "kernel-kvmsmall", "release": "opensuse-leap 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "OPENSUSE-SU-2026:20965-1", "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-20965-1", "released": "2026-06-15T13:44:30Z" }, { "platform": "linux", "product": "kernel-kvmsmall", "release": "sles 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "SUSE-SU-2026:22127-1", "url": "https://patchblox.com/security/fix/linux/suse-su-2026-22127-1", "released": "2026-06-15T13:06:19Z" }, { "platform": "linux", "product": "kernel-obs-build", "release": "opensuse-leap 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "OPENSUSE-SU-2026:20965-1", "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-20965-1", "released": "2026-06-15T13:44:30Z" }, { "platform": "linux", "product": "kernel-obs-qa", "release": "opensuse-leap 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "OPENSUSE-SU-2026:20965-1", "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-20965-1", "released": "2026-06-15T13:44:30Z" }, { "platform": "linux", "product": "kernel-obs-qa", "release": "sles 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "SUSE-SU-2026:22127-1", "url": "https://patchblox.com/security/fix/linux/suse-su-2026-22127-1", "released": "2026-06-15T13:06:19Z" }, { "platform": "linux", "product": "kernel-rt", "release": "opensuse-leap 16.0", "fixedVersion": "6.12.0-160000.35.1", "fix": "OPENSUSE-SU-2026:20965-1", "url": 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"Debian 14", "fixedVersion": "6.19.14-1", "fix": "DEBIAN-CVE-2026-31584", "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-31584", "released": "2026-05-15T16:01:09Z" } ], "noFixYet": [], "dataAsOf": "2026-11-09T01:18:40Z", "attribution": { "text": "Data: Patchblox Patch Radar", "url": "https://patchblox.com/security/patch-radar", "terms": "https://patchblox.com/security/patch-radar/use-the-data" } }