#VU29241 Symlink attack in Mercurial - CVE-2019-3902

Vulnerability identifier: #VU29241

Vulnerability risk: Medium

CVSSv4.0: 0.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2019-3902

CWE-ID: CWE-61

Exploitation vector: Network

Exploit availability: No

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

Vendor: Mercurial

Description

The vulnerability allows a remote user to escalate privileges on the system.

The vulnerability exists due to a symlink following issue. A remote user can create a specially crafted symbolic link to and write files outside a repository.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mercurial: 4.0 - 4.8.2

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External links
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3902
https://lists.debian.org/debian-lts-announce/2019/04/msg00024.html
https://usn.ubuntu.com/4086-1/
https://www.mercurial-scm.org/wiki/WhatsNew#Mercurial_4.9_.282019-02-01.29

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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.