#VU34863 Double Free in libyang - CVE-2019-20393

Vulnerability identifier: #VU34863

Vulnerability risk: High

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2019-20393

CWE-ID: CWE-415

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
libyang
Universal components / Libraries / Libraries used by multiple products

Vendor: CESNET

Description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

A double-free is present in libyang before v1.0-r1 in the function yyparse() when an empty description is used. Applications that use libyang to parse untrusted input yang files may be vulnerable to this flaw, which would cause a crash or potentially code execution.

Mitigation
Install update from vendor's website.

Vulnerable software versions

libyang: 0.11 - 0.16

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External links
http://bugzilla.redhat.com/show_bug.cgi?id=1793930
http://github.com/CESNET/libyang/commit/d9feacc4a590d35dbc1af21caf9080008b4450ed
http://github.com/CESNET/libyang/compare/v0.16-r3...v1.0-r1
http://github.com/CESNET/libyang/issues/742

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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.