CVE-2026-76870: Netcore NR255-V 1.5.130703 Out-of-Bounds Read in mtd_write Firmware Upload Validation
Netcore NR255-V version 1.5.130703 contains an out-of-bounds read vulnerability in the mtdwrite pre-flash validation routine triggered by short firmware uploads. Attackers can upload a truncated firmware image via putfilecgi.c to trigger out-of-bounds reads across main.c, checkimageuuid.c, and oemMD5Update.c.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Netcore NR255-Vto a version that resolves this vulnerability.Fixed in 1.5.130703 - Compensating control
Mitigate the issue by blocking or restricting access to the firmware upload endpoint implemented in put_file_cgi.c (triggering short/truncated uploads) until the vulnerable firmware upload validation routine is fixed.
Event History
Frequently Asked Questions
What level of access does an attacker need to exploit this issue?
The attack is network-accessible but requires low-privileged access. The attacker must be able to submit a truncated firmware image through the firmware upload path.
What operational impact is indicated by the severity vector?
The supplied vector indicates high availability impact and low confidentiality impact, with no integrity impact indicated. Exploitation can trigger out-of-bounds reads during pre-flash image validation.