{"id":"CVE-2026-45878","state":"PUBLISHED","title":"drm/amdkfd: Fix watch_id bounds checking in debug address watch v2","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdkfd: Fix watch_id bounds checking in debug address watch v2\n\nThe address watch clear code receives watch_id as an unsigned value\n(u32), but some helper functions were using a signed int and checked\nbits by shifting with watch_id.\n\nIf a very large watch_id is passed from userspace, it can be converted\nto a negative value.  This can cause invalid shifts and may access\nmemory outside the watch_points array.\n\ndrm/amdkfd: Fix watch_id bounds checking in debug address watch v2\n\nFix this by checking that watch_id is within MAX_WATCH_ADDRESSES before\nusing it.  Also use BIT(watch_id) to test and clear bits safely.\n\nThis keeps the behavior unchanged for valid watch IDs and avoids\nundefined behavior for invalid ones.\n\nFixes the below:\ndrivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c:448\nkfd_dbg_trap_clear_dev_address_watch() error: buffer overflow\n'pdd->watch_points' 4 <= u32max user_rl='0-3,2147483648-u32max' uncapped\n\ndrivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c\n    433 int kfd_dbg_trap_clear_dev_address_watch(struct kfd_process_device *pdd,\n    434                                         uint32_t watch_id)\n    435 {\n    436         int r;\n    437\n    438         if (!kfd_dbg_owns_dev_watch_id(pdd, watch_id))\n\nkfd_dbg_owns_dev_watch_id() doesn't check for negative values so if\nwatch_id is larger than INT_MAX it leads to a buffer overflow.\n(Negative shifts are undefined).\n\n    439                 return -EINVAL;\n    440\n    441         if (!pdd->dev->kfd->shared_resources.enable_mes) {\n    442                 r = debug_lock_and_unmap(pdd->dev->dqm);\n    443                 if (r)\n    444                         return r;\n    445         }\n    446\n    447         amdgpu_gfx_off_ctrl(pdd->dev->adev, false);\n--> 448         pdd->watch_points[watch_id] = pdd->dev->kfd2kgd->clear_address_watch(\n    449                                                         pdd->dev->adev,\n    450                                                         watch_id);\n\nv2: (as per, Jonathan Kim)\n - Add early watch_id >= MAX_WATCH_ADDRESSES validation in the set path to\n   match the clear path.\n - Drop the redundant bounds check in kfd_dbg_owns_dev_watch_id().","publishedAt":"2026-05-27T12:16:49.108Z","updatedAt":"2026-10-19T19:26:39.200Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e0f85f4690d089cc1a60337decafb1acf7eec45e","status":"affected","lessThan":"971bf8e61e9b4abaacf9b35eaf76ec222758f9d6","versionType":"git"},{"version":"e0f85f4690d089cc1a60337decafb1acf7eec45e","status":"affected","lessThan":"a0d367e13db63a6ed76ee0d0a8c3a58c1fa98488","versionType":"git"},{"version":"e0f85f4690d089cc1a60337decafb1acf7eec45e","status":"affected","lessThan":"2b36c0c1bcbbe15f6cfa9652084b3124c835a150","versionType":"git"},{"version":"e0f85f4690d089cc1a60337decafb1acf7eec45e","status":"affected","lessThan":"3c38a0f07aa2bfef2b219b1f045534ad93f85afd","versionType":"git"},{"version":"e0f85f4690d089cc1a60337decafb1acf7eec45e","status":"affected","lessThan":"5a19302cab5cec7ae7f1a60c619951e6c17d8742","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdkfd/kfd_debug.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.5","versionType":"semver"},{"version":"6.6.128","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.75","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.14","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.4","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdkfd/kfd_debug.c"]}],"references":["https://git.kernel.org/stable/c/971bf8e61e9b4abaacf9b35eaf76ec222758f9d6","https://git.kernel.org/stable/c/a0d367e13db63a6ed76ee0d0a8c3a58c1fa98488","https://git.kernel.org/stable/c/2b36c0c1bcbbe15f6cfa9652084b3124c835a150","https://git.kernel.org/stable/c/3c38a0f07aa2bfef2b219b1f045534ad93f85afd","https://git.kernel.org/stable/c/5a19302cab5cec7ae7f1a60c619951e6c17d8742"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/45xxx/CVE-2026-45878.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-45878","state":"PUBLISHED","datePublished":"2026-05-27T12:16:49.108Z","dateUpdated":"2026-10-19T19:26:39.200Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.081Z"},"containers":{"cna":{"title":"drm/amdkfd: Fix watch_id bounds checking in debug address watch v2","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdkfd: Fix watch_id bounds checking in debug address watch v2\n\nThe address watch clear code receives watch_id as an unsigned value\n(u32), but some helper functions were using a signed int and checked\nbits by shifting with watch_id.\n\nIf a very large watch_id is passed from userspace, it can be converted\nto a negative value.  This can cause invalid shifts and may access\nmemory outside the watch_points array.\n\ndrm/amdkfd: Fix watch_id bounds checking in debug address watch v2\n\nFix this by checking that watch_id is within MAX_WATCH_ADDRESSES before\nusing it.  Also use BIT(watch_id) to test and clear bits safely.\n\nThis keeps the behavior unchanged for valid watch IDs and avoids\nundefined behavior for invalid ones.\n\nFixes the below:\ndrivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c:448\nkfd_dbg_trap_clear_dev_address_watch() error: buffer overflow\n'pdd->watch_points' 4 <= u32max user_rl='0-3,2147483648-u32max' uncapped\n\ndrivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c\n    433 int kfd_dbg_trap_clear_dev_address_watch(struct kfd_process_device *pdd,\n    434                                         uint32_t watch_id)\n    435 {\n    436         int r;\n    437\n    438         if (!kfd_dbg_owns_dev_watch_id(pdd, watch_id))\n\nkfd_dbg_owns_dev_watch_id() doesn't check for negative values so if\nwatch_id is larger than INT_MAX it leads to a buffer overflow.\n(Negative shifts are undefined).\n\n    439                 return -EINVAL;\n    440\n    441         if (!pdd->dev->kfd->shared_resources.enable_mes) {\n    442                 r = debug_lock_and_unmap(pdd->dev->dqm);\n    443                 if (r)\n    444                         return r;\n    445         }\n    446\n    447         amdgpu_gfx_off_ctrl(pdd->dev->adev, false);\n--> 448         pdd->watch_points[watch_id] = pdd->dev->kfd2kgd->clear_address_watch(\n    449                                                         pdd->dev->adev,\n    450                                                         watch_id);\n\nv2: (as per, Jonathan Kim)\n - Add early watch_id >= MAX_WATCH_ADDRESSES validation in the set path to\n   match the clear path.\n - Drop the redundant bounds check in kfd_dbg_owns_dev_watch_id()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e0f85f4690d089cc1a60337decafb1acf7eec45e","status":"affected","lessThan":"971bf8e61e9b4abaacf9b35eaf76ec222758f9d6","versionType":"git"},{"version":"e0f85f4690d089cc1a60337decafb1acf7eec45e","status":"affected","lessThan":"a0d367e13db63a6ed76ee0d0a8c3a58c1fa98488","versionType":"git"},{"version":"e0f85f4690d089cc1a60337decafb1acf7eec45e","status":"affected","lessThan":"2b36c0c1bcbbe15f6cfa9652084b3124c835a150","versionType":"git"},{"version":"e0f85f4690d089cc1a60337decafb1acf7eec45e","status":"affected","lessThan":"3c38a0f07aa2bfef2b219b1f045534ad93f85afd","versionType":"git"},{"version":"e0f85f4690d089cc1a60337decafb1acf7eec45e","status":"affected","lessThan":"5a19302cab5cec7ae7f1a60c619951e6c17d8742","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdkfd/kfd_debug.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.5","versionType":"semver"},{"version":"6.6.128","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.75","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.14","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.4","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpu/drm/amd/amdkfd/kfd_debug.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/971bf8e61e9b4abaacf9b35eaf76ec222758f9d6"},{"url":"https://git.kernel.org/stable/c/a0d367e13db63a6ed76ee0d0a8c3a58c1fa98488"},{"url":"https://git.kernel.org/stable/c/2b36c0c1bcbbe15f6cfa9652084b3124c835a150"},{"url":"https://git.kernel.org/stable/c/3c38a0f07aa2bfef2b219b1f045534ad93f85afd"},{"url":"https://git.kernel.org/stable/c/5a19302cab5cec7ae7f1a60c619951e6c17d8742"}],"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 vulnerability is reached only through an ioctl (AMDKFD_IOC_DBG_TRAP) on the local /dev/kfd device node; there is no network or remote path.\nAC:L - The attacker fully controls both the allocation of a watch point and the crafted watch_id; the negative-shift behavior is deterministic on x86, so the out-of-bounds write is triggered reliably and repeatably.\nPR:L - The ioctl has flags=0 with no capability check, and self-debugging (target==p) is permitted, so any unprivileged local user with access to the GPU device node (/dev/kfd) can reach the bug; no root/CAP_SYS_ADMIN is required.\nUI:N - The attacking process performs the enable/allocate/clear sequence entirely on its own; no action by another user is needed.\nS:U - The out-of-bounds write corrupts kernel memory within the same kernel security authority; it does not cross into a separate authority such as a hypervisor or IOMMU boundary.\nC:H - The bug is a kernel out-of-bounds write (memory corruption) that can be groomed to overwrite adjacent kernel structures (e.g., size/pointer fields), which can be leveraged to enable information disclosure.\nI:H - Attacker-influenced out-of-bounds write of a 32-bit value into kernel memory at a controllable offset is a direct kernel memory-corruption/write primitive.\nA:H - The out-of-bounds write into unmapped or critical kernel memory readily causes a kernel oops/panic, producing a denial of service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:28:38.911Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.6.128"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.12.75"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.18.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.19.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-45878","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:18:15.974841Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","type":"CWE","description":"CWE-125 Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:26:39.200Z"}}]}}}