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.

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
syoyo tinyobjloader-c unaffected
Version Status Constraints
0 affected ≤ *

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Fixes

Solution

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Workaround

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References
Link Providers
https://github.com/syoyo/tinyobjloader-c cve-icon
https://github.com/syoyo/tinyobjloader-c/blob/master/tinyobj_loader_c.h cve-icon
History

Wed, 05 Aug 2026 13:15:00 +0000

Type Values Removed Values Added
Description 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.
Title tinyobjloader-c Stack Buffer Overflow in MTL Material File Line Parsing
Weaknesses CWE-121
References
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}

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cve-icon MITRE

Status: PUBLISHED

Assigner: TuranSec

Published:

Updated: 2026-08-05T15:40:58.880Z

Reserved: 2026-08-05T12:23:34.967Z

Link: CVE-2026-71266

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

Updated: 2026-08-05T15:00:05Z

Weaknesses