Vulnerability identifier: #VU34734

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-19945

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
OpenWrt
Operating systems & Components / Operating system

Vendor: openwrt.org

Description

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

uhttpd in OpenWrt through 18.06.5 and 19.x through 19.07.0-rc2 has an integer signedness error. This leads to out-of-bounds access to a heap buffer and a subsequent crash. It can be triggered with an HTTP POST request to a CGI script, specifying both "Transfer-Encoding: chunked" and a large negative Content-Length value.

Mitigation
Install update from vendor's website.

Vulnerable software versions

OpenWrt: 19.07.0

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External links
http://github.com/openwrt/openwrt/commits/master
http://openwrt.org/advisory/2020-01-13-1

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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.