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CVE-2019-20396

22
FAUCET Score

CVE-2019-20396 describes a segmentation fault vulnerability in libyang before version 1.0-r1, specifically within the yyparse function, triggered by a malformed pattern statement value during lys_parse_path parsing. This vulnerability has a CVSS score of 6.5 (Medium), indicating it can be exploited remotely with low attack complexity, leading to high availability impact (denial of service) without requiring user interaction or privileges. There is no evidence of active exploitation, publicly available exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

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

6.5MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.91%
Probability of exploitation in next 30 days
EPSS Percentile
77.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0191 is in the 89th percentile among its peer group of 26,234 CVEs.

Social Chatter

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

Media Mentions

No media coverage found for this CVE.

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

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch 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-2019-20396Moderate

libyang: heap-based buffer over-read in function lys_type_free() due to malformed pattern

Mar 29, 2019

References

github.com / CESNET/libyang/commit/a1f17693904ed6fecc8902c747fc50a8f20e6af8
PatchThird Party Advisory
github.com / CESNET/libyang/compare/v0.16-r3...v1.0-r1
Third Party Advisory
github.com / CESNET/libyang/issues/740
ExploitThird Party Advisory
lists.debian.org / debian-lts-announce/2023/09/msg00019.html