{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43237", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:55.995Z", "datePublished": "2026-05-06T11:28:32.300Z", "dateUpdated": "2026-08-05T12:26:48.364Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:26:48.364Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdgpu: Refactor amdgpu_gem_va_ioctl for Handling Last Fence Update and Timeline Management v4\n\nThis commit simplifies the amdgpu_gem_va_ioctl function, key updates\ninclude:\n - Moved the logic for managing the last update fence directly into\n amdgpu_gem_va_update_vm.\n - Introduced checks for the timeline point to enable conditional\n replacement or addition of fences.\n\nv2: Addressed review comments from Christian.\nv3: Updated comments (Christian).\nv4: The previous version selected the fence too early and did not manage its\n reference correctly, which could lead to stale or freed fences being used.\n This resulted in refcount underflows and could crash when updating GPU\n timelines.\n The fence is now chosen only after the VA mapping work is completed, and its\n reference is taken safely. After exporting it to the VM timeline syncobj, the\n driver always drops its local fence reference, ensuring balanced refcounting\n and avoiding use-after-free on dma_fence.\n\n\tCrash signature:\n\t[ 205.828135] refcount_t: underflow; use-after-free.\n\t[ 205.832963] WARNING: CPU: 30 PID: 7274 at lib/refcount.c:28 refcount_warn_saturate+0xbe/0x110\n\t...\n\t[ 206.074014] Call Trace:\n\t[ 206.076488] \n\t[ 206.078608] amdgpu_gem_va_ioctl+0x6ea/0x740 [amdgpu]\n\t[ 206.084040] ? __pfx_amdgpu_gem_va_ioctl+0x10/0x10 [amdgpu]\n\t[ 206.089994] drm_ioctl_kernel+0x86/0xe0 [drm]\n\t[ 206.094415] drm_ioctl+0x26e/0x520 [drm]\n\t[ 206.098424] ? __pfx_amdgpu_gem_va_ioctl+0x10/0x10 [amdgpu]\n\t[ 206.104402] amdgpu_drm_ioctl+0x4b/0x80 [amdgpu]\n\t[ 206.109387] __x64_sys_ioctl+0x96/0xe0\n\t[ 206.113156] do_syscall_64+0x66/0x2d0\n\t...\n\t[ 206.553351] BUG: unable to handle page fault for address: ffffffffc0dfde90\n\t...\n\t[ 206.553378] RIP: 0010:dma_fence_signal_timestamp_locked+0x39/0xe0\n\t...\n\t[ 206.553405] Call Trace:\n\t[ 206.553409] \n\t[ 206.553415] ? __pfx_drm_sched_fence_free_rcu+0x10/0x10 [gpu_sched]\n\t[ 206.553424] dma_fence_signal+0x30/0x60\n\t[ 206.553427] drm_sched_job_done.isra.0+0x123/0x150 [gpu_sched]\n\t[ 206.553434] dma_fence_signal_timestamp_locked+0x6e/0xe0\n\t[ 206.553437] dma_fence_signal+0x30/0x60\n\t[ 206.553441] amdgpu_fence_process+0xd8/0x150 [amdgpu]\n\t[ 206.553854] sdma_v4_0_process_trap_irq+0x97/0xb0 [amdgpu]\n\t[ 206.554353] edac_mce_amd(E) ee1004(E)\n\t[ 206.554270] amdgpu_irq_dispatch+0x150/0x230 [amdgpu]\n\t[ 206.554702] amdgpu_ih_process+0x6a/0x180 [amdgpu]\n\t[ 206.555101] amdgpu_irq_handler+0x23/0x60 [amdgpu]\n\t[ 206.555500] __handle_irq_event_percpu+0x4a/0x1c0\n\t[ 206.555506] handle_irq_event+0x38/0x80\n\t[ 206.555509] handle_edge_irq+0x92/0x1e0\n\t[ 206.555513] __common_interrupt+0x3e/0xb0\n\t[ 206.555519] common_interrupt+0x80/0xa0\n\t[ 206.555525] \n\t[ 206.555527] \n\t...\n\t[ 206.555650] RIP: 0010:dma_fence_signal_timestamp_locked+0x39/0xe0\n\t...\n\t[ 206.555667] Kernel panic - not syncing: Fatal exception in interrupt" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable path is reached through the local AMDGPU DRM `AMDGPU_GEM_VA` ioctl on `/dev/dri` render/primary nodes, not via network packets or physical hotplug.\nAC:L - The attacker controls the ioctl sequence, GEM objects, VM mappings, syncobj timeline output, and can repeatedly trigger the fence lifetime bug without relying on conditions outside their control.\nPR:L - The ioctl is `DRM_AUTH|DRM_RENDER_ALLOW`, so an unprivileged local user with access to the AMDGPU render node can reach it; no real root or init-namespace capability is required.\nUI:N - Once the attacker has local access to the device node, exploitation only requires issuing ioctls and does not require any victim user action.\nS:U - The bug corrupts kernel/driver synchronization state from within the same host kernel security authority; it is not a VM escape or IOMMU/DMA boundary bypass.\nC:H - The bug is a use-after-free/stale `dma_fence` reference in kernel memory, and such fence object reuse can be groomed into broader kernel memory disclosure primitives.\nI:H - The freed `dma_fence` contains pointers, callback lists, and synchronization state used later by kernel code, making control-flow or arbitrary kernel memory modification defensible for scoring.\nA:H - The documented failure includes refcount underflow, page fault in `dma_fence_signal_timestamp_locked`, interrupt-context crash, and kernel panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c" ], "versions": [ { "version": "70773bef4e091ff6d2a91e3dfb4f29013eb81f1f", "lessThan": "e9e477d3197f7d8955a042c0d7f53f78f13218ba", "status": "affected", "versionType": "git" }, { "version": "70773bef4e091ff6d2a91e3dfb4f29013eb81f1f", "lessThan": "0399b8416ecf64ef86ad23401fe23eabdb07831a", "status": "affected", "versionType": "git" }, { "version": "70773bef4e091ff6d2a91e3dfb4f29013eb81f1f", "lessThan": "bd8150a1b3370a9f7761c5814202a3fe5a79f44f", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c" ], "versions": [ { "version": "6.16", "status": "affected" }, { "version": "0", "lessThan": "6.16", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.16", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.6", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "6.18.16" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "6.19.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/e9e477d3197f7d8955a042c0d7f53f78f13218ba" }, { "url": "https://git.kernel.org/stable/c/0399b8416ecf64ef86ad23401fe23eabdb07831a" }, { "url": "https://git.kernel.org/stable/c/bd8150a1b3370a9f7761c5814202a3fe5a79f44f" } ], "title": "drm/amdgpu: Refactor amdgpu_gem_va_ioctl for Handling Last Fence Update and Timeline Management v4", "x_generator": { "engine": "bippy-1.2.0" } } } }