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Fencer Intel
high 8.8

CVE-2019-20393 json

A double-free is present in libyang before v1.0-r1 in the function yyparse() when an empty description is used.

published 6y ago modified 4mo ago also EUVD-2019-10943

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.8%
EPSS 2.8% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

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.

Patch / fix

  • libyang Debian 14, Debian 13 1.0.176-1

debian advisories DEBIAN-CVE-2019-20393

  • libyang RHEL 8 1.0.184-1.el8

red hat advisories RHEA-2021:1906

  • libyang AlmaLinux 8 1.0.184-1.el8

almalinux advisories ALEA-2021:1906

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-20393 updated cvss 7.0

libyang: double-free in function yyparse() when empty description is used

  • Red Hat Enterprise Linux AppStream (v. 8) libyang 1.0.184-1.el8
    fixed: vendor fix RHEA-2021:1906

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.84% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/CESNET/libyang/issues/742 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.