Null pointer dereference in ngx_chain_to_iovec() in nginx (Alpine package)

1) Null pointer dereference in ngx_chain_to_iovec()

EUVDB-ID: #VU25

Risk: Medium

CVSSv3.1: 6.5 [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-2016-4450

CWE-ID: CWE-829 - Inclusion of Functionality from Untrusted Control Sphere

Exploit availability: No

Description

The vulnerability allows a remote attacker to cause denial of service conditions on the target system.

The vulnerability exists due to an access control error in the ngx_chain_to_iovec() function, when saving the client request body to a temporary file. A remote unauthenticated attacker can cause a null pointer dereference in the ngx_chain_to_iovec() function by sending specially crafted data.

Successful exploitation of this vulnerability may lead to the crash of a worker process.

Mitigation

Install update from vendor's website.

Vulnerable software versions

nginx (Alpine package): 1.4.3-r0 - 1.6.2-r1

External links

http://git.alpinelinux.org/aports/commit/?id=1fbaa57d3e6c35e0dd9b37ced3e7b4f3dfbab621
http://git.alpinelinux.org/aports/commit/?id=6123c2137e443bed33d0c3aa9f520199843021e3
http://git.alpinelinux.org/aports/commit/?id=c2b7b271e326df743f057bae203706af5b8efc92

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.