#VU26371 Out-of-bounds write in OpenWrt - CVE-2020-7248

Vulnerability identifier: #VU26371

Vulnerability risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2020-7248

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
OpenWrt
Operating systems & Components / Operating system

Vendor: openwrt.org

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing untrusted input in libubox library. A remote attacker can provide a specially crafted binary blob or JSON input to "blobmsg_format_json", trigger out-of-bounds write and execute arbitrary code on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

OpenWrt: 18.06.0 - 18.06.6, 19.07.0

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External links
https://github.com/openwrt/openwrt/commits/master
https://openwrt.org/advisory/2020-01-31-2

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.