CVE-2019-20393

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-01-22 · updated 2026-06-17
Weakness: CWE-415

Description

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.

Affected products

CESNET libyang: 0.11-r1, 0.11-r2, 0.12-r1, 0.12-r2, 0.13-r1, 0.13-r2 (+5)

References

https://bugzilla.redhat.com/show_bug.cgi?id=1793930
https://github.com/CESNET/libyang/commit/d9feacc4a590d35dbc1af21caf9080008b4450ed
https://github.com/CESNET/libyang/compare/v0.16-r3...v1.0-r1
https://github.com/CESNET/libyang/issues/742
https://lists.debian.org/debian-lts-announce/2023/09/msg00019.html
https://bugzilla.redhat.com/show_bug.cgi?id=1793930
https://github.com/CESNET/libyang/commit/d9feacc4a590d35dbc1af21caf9080008b4450ed
https://github.com/CESNET/libyang/compare/v0.16-r3...v1.0-r1
https://github.com/CESNET/libyang/issues/742
https://lists.debian.org/debian-lts-announce/2023/09/msg00019.html

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