GHSA-8H36-WFWW-P7V6
Vulnerability from github – Published: 2026-06-03 18:33 – Updated: 2026-06-05 09:33In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix out-of-bounds stream encoder index v3
eng_id can be negative and that stream_enc_regs[] can be indexed out of bounds.
eng_id is used directly as an index into stream_enc_regs[], which has only 5 entries. When eng_id is 5 (ENGINE_ID_DIGF) or negative, this can access memory past the end of the array.
Add a bounds check using ARRAY_SIZE() before using eng_id as an index. The unsigned cast also rejects negative values.
This avoids out-of-bounds access.
Fixes the below smatch error: dcn*_resource.c: stream_encoder_create() may index stream_enc_regs[eng_id] out of bounds (size 5).
drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn351/dcn351_resource.c 1246 static struct stream_encoder dcn35_stream_encoder_create( 1247 enum engine_id eng_id, 1248 struct dc_context ctx) 1249 {
...
1255
1256 /* Mapping of VPG, AFMT, DME register blocks to DIO block instance */
1257 if (eng_id <= ENGINE_ID_DIGF) {
ENGINE_ID_DIGF is 5. should <= be <?
Unrelated but, ugh, why is Smatch saying that "eng_id" can be negative? end_id is type signed long, but there are checks in the caller which prevent it from being negative.
1258 vpg_inst = eng_id;
1259 afmt_inst = eng_id;
1260 } else
1261 return NULL;
1262
...
1281
1282 dcn35_dio_stream_encoder_construct(enc1, ctx, ctx->dc_bios,
1283 eng_id, vpg, afmt,
--> 1284 &stream_enc_regs[eng_id], ^^^^^^^^^^^^^^^^^^^^^^^ This stream_enc_regs[] array has 5 elements so we are one element beyond the end of the array.
...
1287 return &enc1->base;
1288 }
v2: use explicit bounds check as suggested by Roman/Dan; avoid unsigned int cast
v3: The compiler already knows how to compare the two values, so the cast (int) is not needed. (Roman)
{
"affected": [],
"aliases": [
"CVE-2026-46263"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-03T18:16:27Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: Fix out-of-bounds stream encoder index v3\n\neng_id can be negative and that stream_enc_regs[]\ncan be indexed out of bounds.\n\neng_id is used directly as an index into stream_enc_regs[], which has\nonly 5 entries. When eng_id is 5 (ENGINE_ID_DIGF) or negative, this can\naccess memory past the end of the array.\n\nAdd a bounds check using ARRAY_SIZE() before using eng_id as an index.\nThe unsigned cast also rejects negative values.\n\nThis avoids out-of-bounds access.\n\nFixes the below smatch error:\ndcn*_resource.c: stream_encoder_create() may index\nstream_enc_regs[eng_id] out of bounds (size 5).\n\ndrivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn351/dcn351_resource.c\n 1246 static struct stream_encoder *dcn35_stream_encoder_create(\n 1247 enum engine_id eng_id,\n 1248 struct dc_context *ctx)\n 1249 {\n\n ...\n\n 1255\n 1256 /* Mapping of VPG, AFMT, DME register blocks to DIO block instance */\n 1257 if (eng_id \u003c= ENGINE_ID_DIGF) {\n\nENGINE_ID_DIGF is 5. should \u003c= be \u003c?\n\nUnrelated but, ugh, why is Smatch saying that \"eng_id\" can be negative?\nend_id is type signed long, but there are checks in the caller which prevent it from being negative.\n\n 1258 vpg_inst = eng_id;\n 1259 afmt_inst = eng_id;\n 1260 } else\n 1261 return NULL;\n 1262\n\n ...\n\n 1281\n 1282 dcn35_dio_stream_encoder_construct(enc1, ctx, ctx-\u003edc_bios,\n 1283 eng_id, vpg, afmt,\n--\u003e 1284 \u0026stream_enc_regs[eng_id],\n ^^^^^^^^^^^^^^^^^^^^^^^ This stream_enc_regs[] array has 5 elements so we are one element beyond the end of the array.\n\n ...\n\n 1287 return \u0026enc1-\u003ebase;\n 1288 }\n\nv2: use explicit bounds check as suggested by Roman/Dan; avoid unsigned int cast\n\nv3: The compiler already knows how to compare the two values, so the\n cast (int) is not needed. (Roman)",
"id": "GHSA-8h36-wfww-p7v6",
"modified": "2026-06-05T09:33:46Z",
"published": "2026-06-03T18:33:12Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46263"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/263e28add4f4472cfa95150d218955d1945aa413"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/29f3824b08a98d41ecbbfd33580630d7607f962e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/abde491143e4e12eecc41337910aace4e8d59603"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ca3808d560ad946ab6d089fd1f5bee04b952ead4"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
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