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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-71266
StatePUBLISHED
AssignerTuranSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-05 13:24:50 UTC
Updated2026-08-05 16:17:05 UTC
Descriptiontinyobjloader-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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c

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

EPSS: 0.001270000 probability, percentile 0.027370000 (date 2026-08-07)

Problem Types: CWE-121 | CWE-121 CWE-121

VersionSourceTypeScoreSeverityVector
3.1309f9ea4-e3e9-4c6c-b79d-e8eb01244f2cSecondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Syoyo Tinyobjloader-c affected * custom Not specified

References

ReferenceSourceLinkTags
github.com/syoyo/tinyobjloader-c/blob/master/tinyobj_loader_c.h 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c github.com
github.com/syoyo/tinyobjloader-c 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Alibek Baxtiyorov (en)

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