FKIE_CVE-2026-46263

Vulnerability from fkie_nvd - Published: 2026-06-03 18:16 - Updated: 2026-06-05 07:16
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In 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)
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/263e28add4f4472cfa95150d218955d1945aa413
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/29f3824b08a98d41ecbbfd33580630d7607f962e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/abde491143e4e12eecc41337910aace4e8d59603
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ca3808d560ad946ab6d089fd1f5bee04b952ead4
Impacted products
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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": "CVE-2026-46263",
  "lastModified": "2026-06-05T07:16:31.790",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-06-03T18:16:27.743",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/263e28add4f4472cfa95150d218955d1945aa413"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/29f3824b08a98d41ecbbfd33580630d7607f962e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/abde491143e4e12eecc41337910aace4e8d59603"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ca3808d560ad946ab6d089fd1f5bee04b952ead4"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}


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