CVE-2026-89809
In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: fix scope of mqd_mgr dereference in pqm_debugfs_mqds
Reading /sys/kernel/debug/kfd/mqds while a process holds an active KFD queue triggers a NULL pointer dereference because the for loop that calls mqd_mgr->debugfs_show_mqd() is incorrectly placed outside the if (pqn->q) block that initializes mqd_mgr.
The queue list can contain entries where pqn->q is NULL (kernel queues where only pqn->kq is valid). In the original code:
When iterating over a queue node where pqn->q is NULL: 1. The if (pqn->q) block is skipped 2. mqd_mgr remains uninitialized (NULL from declaration) 3. The for loop executes anyway 4. mqd_mgr->debugfs_show_mqd(m, mqd) dereferences NULL
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The crash manifests as:
Fix by moving the for loop inside the if (pqn->q) block, so mqd_mgr and related variables are only used when properly initialized.
(cherry picked from commit 8bfe29d5c798940f797aa24135d2734c3ffce9de)
Detalles técnicos trazas, registros y código del informe original
if (pqn->q) {
...
mqd_mgr = q->device->dqm->mqd_mgrs[mqd_type];
size = mqd_mgr->mqd_stride(...);
}
for (xcc = 0; xcc < num_xccs; xcc++) { // WRONG: outside if block
mqd = q->mqd + size * xcc;
r = mqd_mgr->debugfs_show_mqd(m, mqd);
}
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
RIP: 0010:0x0
Call Trace:
pqm_debugfs_mqds+0x10c/0x1d0 [amdgpu]
kfd_debugfs_mqds_by_process+0x9b/0x110 [amdgpu]
seq_read_iter+0x132/0x4b0
...CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.20%
- Percentil entre todas las CVEs puntuadas: 9
- Fecha de la puntuación: 4/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
JSON original (NVD)
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{
"id": "CVE-2026-89809",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "e1b73b64271d706079370b58b81292dafd373163",
"lessThan": "58e866711b234571b0ce342c43d153a4786b32b8",
"versionType": "git"
},
{
"status": "affected",
"version": "e1b73b64271d706079370b58b81292dafd373163",
"lessThan": "012a026bae0212952b423a842b7e2c0bf21f8e7a",
"versionType": "git"
}
],
"programFiles": [
"drivers/gpu/drm/amd/amdkfd/kfd_process_queue_manager.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "7.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3-rc2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/gpu/drm/amd/amdkfd/kfd_process_queue_manager.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-09-16T11:16:46.047",
"references": [
{
"url": "https://git.kernel.org/stable/c/012a026bae0212952b423a842b7e2c0bf21f8e7a",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/58e866711b234571b0ce342c43d153a4786b32b8",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "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)"
}
],
"lastModified": "2026-09-17T10:17:04.047",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}