#VU34865 Resource exhaustion in libyang - CVE-2019-20395

Vulnerability identifier: #VU34865

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2019-20395

CWE-ID: CWE-400

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 perform a denial of service (DoS) attack.

A stack consumption issue is present in libyang before v1.0-r1 due to the self-referential union type containing leafrefs. Applications that use libyang to parse untrusted input yang files may crash.

Mitigation
Install update from vendor's website.

Vulnerable software versions

libyang: 0.11 - 0.16

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External links
https://bugzilla.redhat.com/show_bug.cgi?id=1793924
https://github.com/CESNET/libyang/commit/4e610ccd87a2ba9413819777d508f71163fcc237
https://github.com/CESNET/libyang/compare/v0.16-r3...v1.0-r1
https://github.com/CESNET/libyang/issues/724

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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.