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CVE-2019-20397

27
FAUCET Score

CVE-2019-20397 is a double-free vulnerability in cesnet libyang versions prior to v1.0-r1, specifically within the yyparse() function when an organization field lacks proper termination. This flaw, rated 8.8 HIGH (CVSS:3.1), allows unauthenticated attackers to trigger a crash or potentially achieve remote code execution by enticing a user to parse a specially crafted, untrusted YANG file. While the vulnerability presents a high risk due to its network attack vector and low complexity, there is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
0.11CPE matchmatch criteria
cpe:2.3:a:cesnet:libyang:0.11:r1:*:*:*:*:*:*
0.11CPE matchmatch criteria
cpe:2.3:a:cesnet:libyang:0.11:r2:*:*:*:*:*:*
0.12CPE matchmatch criteria
cpe:2.3:a:cesnet:libyang:0.12:r1:*:*:*:*:*:*
0.12CPE matchmatch criteria
cpe:2.3:a:cesnet:libyang:0.12:r2:*:*:*:*:*:*
0.13CPE matchmatch criteria
cpe:2.3:a:cesnet:libyang:0.13:r1:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.8HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.49%
Probability of exploitation in next 30 days
EPSS Percentile
82.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0249 is in the 82nd percentile among its peer group of 14,825 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.1 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

github_advisorypatch availablevia nvd_reference
View patch
redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: libyang-0:1.0.184-1.el8
View patch

Vendor Advisories (1)

redhatCVE-2019-20397Moderate

libyang: double-free in yyparse() when organization field is not terminated

Mar 28, 2019

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
github.com / CESNET/libyang/commit/88bd6c548ba79bce176cd875e9b56e7e0ef4d8d4
PatchThird Party Advisory
github.com / CESNET/libyang/compare/v0.16-r3...v1.0-r1
Third Party Advisory
github.com / CESNET/libyang/issues/739
Third Party Advisory
lists.debian.org / debian-lts-announce/2023/09/msg00019.html