CVE-2026-76870

HIGH 7.1

Netcore NR255-V 1.5.130703 Out-of-Bounds Read in mtd_write Firmware Upload Validation

CVSS Score

7.1

EPSS Score

0.0%

EPSS Percentile

0th

Netcore NR255-V version 1.5.130703 contains an out-of-bounds read vulnerability in the mtd_write pre-flash validation routine triggered by short firmware uploads. Attackers can upload a truncated firmware image via put_file_cgi.c to trigger out-of-bounds reads across main.c, check_image_uuid.c, and oemMD5Update.c.

CWE	CWE-125
Vendor	netcore
Product	nr255-v
Published	Sep 15, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Affected Versions

Netcore / NR255-V

1.5.130703

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/draw-ctf/netcore-router-public-refs/blob/main/2026.08.19-netcore-nr255v-firmware-upload-oob.md vulncheck.com: https://www.vulncheck.com/advisories/netcore-nr255-v-1.5.130703-out-of-bounds-read-in-mtd-write-firmware-upload-validation

Credits

Zhou Ao Yin Luxing Jiang Yuxuan Liu Xin @Nebusec