{"id":"AZL-83216","summary":"CVE-2026-31488 affecting package kernel for versions less than 6.6.141.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: Do not skip unrelated mode changes in DSC validation\n\nStarting with commit 17ce8a6907f7 (\"drm/amd/display: Add dsc pre-validation in\natomic check\"), amdgpu resets the CRTC state mode_changed flag to false when\nrecomputing the DSC configuration results in no timing change for a particular\nstream.\n\nHowever, this is incorrect in scenarios where a change in MST/DSC configuration\nhappens in the same KMS commit as another (unrelated) mode change. For example,\nthe integrated panel of a laptop may be configured differently (e.g., HDR\nenabled/disabled) depending on whether external screens are attached. In this\ncase, plugging in external DP-MST screens may result in the mode_changed flag\nbeing dropped incorrectly for the integrated panel if its DSC configuration\ndid not change during precomputation in pre_validate_dsc().\n\nAt this point, however, dm_update_crtc_state() has already created new streams\nfor CRTCs with DSC-independent mode changes. In turn,\namdgpu_dm_commit_streams() will never release the old stream, resulting in a\nmemory leak. amdgpu_dm_atomic_commit_tail() will never acquire a reference to\nthe new stream either, which manifests as a use-after-free when the stream gets\ndisabled later on:\n\nBUG: KASAN: use-after-free in dc_stream_release+0x25/0x90 [amdgpu]\nWrite of size 4 at addr ffff88813d836524 by task kworker/9:9/29977\n\nWorkqueue: events drm_mode_rmfb_work_fn\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x6e/0xa0\n print_address_description.constprop.0+0x88/0x320\n ? dc_stream_release+0x25/0x90 [amdgpu]\n print_report+0xfc/0x1ff\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __virt_addr_valid+0x225/0x4e0\n ? dc_stream_release+0x25/0x90 [amdgpu]\n kasan_report+0xe1/0x180\n ? dc_stream_release+0x25/0x90 [amdgpu]\n kasan_check_range+0x125/0x200\n dc_stream_release+0x25/0x90 [amdgpu]\n dc_state_destruct+0x14d/0x5c0 [amdgpu]\n dc_state_release.part.0+0x4e/0x130 [amdgpu]\n dm_atomic_destroy_state+0x3f/0x70 [amdgpu]\n drm_atomic_state_default_clear+0x8ee/0xf30\n ? drm_mode_object_put.part.0+0xb1/0x130\n __drm_atomic_state_free+0x15c/0x2d0\n atomic_remove_fb+0x67e/0x980\n\nSince there is no reliable way of figuring out whether a CRTC has unrelated\nmode changes pending at the time of DSC validation, remember the value of the\nmode_changed flag from before the point where a CRTC was marked as potentially\naffected by a change in DSC configuration. Reset the mode_changed flag to this\nearlier value instead in pre_validate_dsc().\n\n(cherry picked from commit cc7c7121ae082b7b82891baa7280f1ff2608f22b)","modified":"2026-09-09T05:29:25Z","published":"2026-04-22T14:16:46Z","upstream":["CVE-2026-31488"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31488"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.141.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-83216.json"}}],"schema_version":"1.9.0"}