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GHSA-GR59-P4Q8-R75G

Vulnerability from github – Published: 2026-08-05 15:32 – Updated: 2026-08-05 15:32

Details

tinyobjloader-c's tinyobj_parse_and_index_mtl_file() (tinyobj_loader_c.h) reads each line of a .mtl material file into a fixed 4096-byte stack buffer linebuf via memcpy(linebuf, p, p_len), guarded only by assert(p_len < 4095). Because assert() compiles to a no-op under -DNDEBUG (standard for release builds), a crafted .mtl file containing a line (e.g. a "newmtl" material name) longer than 4096 bytes overflows linebuf into the adjacent stack variable namebuf and beyond, corrupting the stack of any application that loads attacker-supplied 3D model/material files. The identical vulnerable pattern is duplicated in a second function in the same file.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-71266"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-121"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-05T13:24:50Z",
    "severity": "HIGH"
  },
  "details": "tinyobjloader-c\u0027s tinyobj_parse_and_index_mtl_file() (tinyobj_loader_c.h) reads each line of a .mtl material file into a fixed 4096-byte stack buffer `linebuf` via memcpy(linebuf, p, p_len), guarded only by `assert(p_len \u003c 4095)`. Because assert() compiles to a no-op under -DNDEBUG (standard for release builds), a crafted .mtl file containing a line (e.g. a \"newmtl\" material name) longer than 4096 bytes overflows linebuf into the adjacent stack variable namebuf and beyond, corrupting the stack of any application that loads attacker-supplied 3D model/material files. The identical vulnerable pattern is duplicated in a second function in the same file.",
  "id": "GHSA-gr59-p4q8-r75g",
  "modified": "2026-08-05T15:32:19Z",
  "published": "2026-08-05T15:32:19Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-71266"
    },
    {
      "type": "WEB",
      "url": "https://github.com/syoyo/tinyobjloader-c"
    },
    {
      "type": "WEB",
      "url": "https://github.com/syoyo/tinyobjloader-c/blob/master/tinyobj_loader_c.h"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-71266 (GCVE-0-2026-71266)

Vulnerability from cvelistv5 – Published: 2026-08-05 12:26 – Updated: 2026-08-05 15:40

Title

tinyobjloader-c Stack Buffer Overflow in MTL Material File Line Parsing

Summary

tinyobjloader-c's tinyobj_parse_and_index_mtl_file() (tinyobj_loader_c.h) reads each line of a .mtl material file into a fixed 4096-byte stack buffer `linebuf` via memcpy(linebuf, p, p_len), guarded only by `assert(p_len < 4095)`. Because assert() compiles to a no-op under -DNDEBUG (standard for release builds), a crafted .mtl file containing a line (e.g. a "newmtl" material name) longer than 4096 bytes overflows linebuf into the adjacent stack variable namebuf and beyond, corrupting the stack of any application that loads attacker-supplied 3D model/material files. The identical vulnerable pattern is duplicated in a second function in the same file.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-121

Assigner

TuranSec

References

2 references

URL	Tags
https://github.com/syoyo/tinyobjloader-c
https://github.com/syoyo/tinyobjloader-c/blob/mas…

Impacted products

1 product

Vendor	Product	Version
syoyo	tinyobjloader-c	Affected: 0 , ≤ * (custom)

Credits

Alibek Baxtiyorov

Show details on NVD website

JSON

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                "id": "CVE-2026-71266",
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                  },
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                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-05T15:40:51.537969Z",
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      "descriptions": [
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          "lang": "en",
          "value": "tinyobjloader-c\u0027s tinyobj_parse_and_index_mtl_file() (tinyobj_loader_c.h) reads each line of a .mtl material file into a fixed 4096-byte stack buffer `linebuf` via memcpy(linebuf, p, p_len), guarded only by `assert(p_len \u003c 4095)`. Because assert() compiles to a no-op under -DNDEBUG (standard for release builds), a crafted .mtl file containing a line (e.g. a \"newmtl\" material name) longer than 4096 bytes overflows linebuf into the adjacent stack variable namebuf and beyond, corrupting the stack of any application that loads attacker-supplied 3D model/material files. The identical vulnerable pattern is duplicated in a second function in the same file."
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      "metrics": [
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          "url": "https://github.com/syoyo/tinyobjloader-c/blob/master/tinyobj_loader_c.h"
        }
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      "title": "tinyobjloader-c Stack Buffer Overflow in MTL Material File Line Parsing"
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

GHSA-GR59-P4Q8-R75G

CVE-2026-71266 (GCVE-0-2026-71266)

Tags

Sightings

Nomenclature