#VU7220 Remote code execution in Mercurial - CVE-2017-9462

Vulnerability identifier: #VU7220

Vulnerability risk: High

CVSSv4.0: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber]

CVE-ID: CVE-2017-9462

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Mercurial
Client/Desktop applications / Other client software

Vendor: Mercurial

Description
The vulnerability allows a remote authenticated attacker to execute arbitrary code on the target system.

The weakness exists due to improper input validation in "hg serve --stdio". A remote attacker can use --debugger as a repository name and consequently execute arbitrary code with privileges of the current user.

Successful exploitation of the vulnerability may result in system compromise.

Mitigation
Update to version 4.1.3 or later.

Vulnerable software versions

Mercurial: 3.4.0 - 4.1.2

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External links
https://www.mercurial-scm.org/repo/hg/rev/77eaf9539499

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.