{"cve":"CVE-2026-89809","nvd":{"published":"2026-09-16T11:16:46.047","modified":"2026-10-19T09:18:24.727","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds\n\nReading /sys/kernel/debug/kfd/mqds while a process holds an active KFD\nqueue triggers a NULL pointer dereference because the for loop that\ncalls mqd_mgr->debugfs_show_mqd() is incorrectly placed outside the\nif (pqn->q) block that initializes mqd_mgr.\n\nThe queue list can contain entries where pqn->q is NULL (kernel queues\nwhere only pqn->kq is valid). In the original code:\n\n  if (pqn->q) {\n      ...\n      mqd_mgr = q->device->dqm->mqd_mgrs[mqd_type];\n      size = mqd_mgr->mqd_stride(...);\n  }\n\n  for (xcc = 0; xcc < num_xccs; xcc++) {  // WRONG: outside if block\n      mqd = q->mqd + size * xcc;\n      r = mqd_mgr->debugfs_show_mqd(m, mqd);\n  }\n\nWhen iterating over a queue node where pqn->q is NULL:\n1. The if (pqn->q) block is skipped\n2. mqd_mgr remains uninitialized (NULL from declaration)\n3. The for loop executes anyway\n4. mqd_mgr->debugfs_show_mqd(m, mqd) dereferences NULL\n\nThe crash manifests as:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000000\n  #PF: supervisor instruction fetch in kernel mode\n  RIP: 0010:0x0\n  Call Trace:\n   pqm_debugfs_mqds+0x10c/0x1d0 [amdgpu]\n   kfd_debugfs_mqds_by_process+0x9b/0x110 [amdgpu]\n   seq_read_iter+0x132/0x4b0\n   ...\n\nFix by moving the for loop inside the if (pqn->q) block, so mqd_mgr\nand related variables are only used when properly initialized.\n\n(cherry picked from commit 8bfe29d5c798940f797aa24135d2734c3ffce9de)","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/012a026bae0212952b423a842b7e2c0bf21f8e7a","https://git.kernel.org/stable/c/58e866711b234571b0ce342c43d153a4786b32b8"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:54:41.405518556+00:00"},"epss":{"cve":"CVE-2026-89809","score":0.00198,"percentile":0.09421,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}