How severe is CVE-2019-20391?

CVE-2019-20391 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2019-20391 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-20391?

CVE-2019-20391 primarily affects Cesnet Libyang. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-20391?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2019-20391 published?

CVE-2019-20391 was published on 2020-01-22 and last updated on 2026-06-17.

CVE-2019-20391

CVE-2019-20391 is a medium-severity vulnerability in Cesnet Libyang with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.3
EPSS exploit prediction: 2% (77th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Cesnet Libyang
Published: 2020-01-22
Last modified: 2026-06-17

Description

An invalid memory access flaw is present in libyang before v1.0-r3 in the function resolve_feature_value() when an if-feature statement is used inside a bit. Applications that use libyang to parse untrusted input yang files may crash.

Frequently asked questions

What is CVE-2019-20391?: An invalid memory access flaw is present in libyang before v1.0-r3 in the function resolve_feature_value() when an if-feature statement is used inside a bit. Applications that use libyang to parse untrusted input yang files may crash.
How severe is CVE-2019-20391?: CVE-2019-20391 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2019-20391 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-20391?: CVE-2019-20391 primarily affects Cesnet Libyang. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-20391?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-20391 published?: CVE-2019-20391 was published on 2020-01-22 and last updated on 2026-06-17.

References

Affected products (13)

cpe:2.3:a:cesnet:libyang:0.11:r1:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:0.11:r2:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:0.12:r1:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:0.12:r2:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:0.13:r1:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:0.13:r2:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:0.14:r1:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:0.15:r1:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:0.16:r1:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:0.16:r2:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:0.16:r3:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:1.0:r1:*:*:*:*:*:*
cpe:2.3:a:cesnet:libyang:1.0:r2:*:*:*:*:*:*

More vulnerabilities in Cesnet Libyang

CVE-2019-19334 — Critical (CVSS 9.8): In all versions of libyang before 1.0-r5, a stack-based buffer overflow was discovered in the way libyang parses YANG…
CVE-2019-19333 — Critical (CVSS 9.8): In all versions of libyang before 1.0-r5, a stack-based buffer overflow was discovered in the way libyang parses YANG…
CVE-2019-20397 — High (CVSS 8.8): A double-free is present in libyang before v1.0-r1 in the function yyparse() when an organization field is not…
CVE-2019-20394 — High (CVSS 8.8): A double-free is present in libyang before v1.0-r3 in the function yyparse() when a type statement in used in a…
CVE-2019-20393 — High (CVSS 8.8): A double-free is present in libyang before v1.0-r1 in the function yyparse() when an empty description is used.…
CVE-2023-26917 — High (CVSS 7.5): libyang from v2.0.164 to v2.1.30 was discovered to contain a NULL pointer dereference via the function…

All CVEs affecting Cesnet Libyang →

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CVE-2022-27624 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2020-11896 — Critical (CVSS 10.0): The Treck TCP/IP stack before 6.0.1.66 allows Remote Code Execution, related to IPv4 tunneling.

Browse all CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities →