CVE-2019-20394Public exploitNetwork attack vector

Code execution via parser-state double free

Published Jan 22, 2020 · Updated Aug 5, 2024

Double-free in libyang before 1.0-r3 allows attackers to crash a consuming application or execute code via a crafted YANG file. In yyparse, entering a notification after parsing a nested type statement leaves parser pointer s live, so later cleanup frees the same allocation twice. The condition is reachable only when a consuming application parses untrusted YANG input, producing heap corruption that crashes the process and can enable code execution.

CVSS severity8.8
High
EPSS probability2.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double-free in libyang before 1.0-r3 allows attackers to crash a consuming application or execute code via a crafted YANG file. In yyparse, entering a notification after parsing a nested type statement leaves parser pointer s live, so later cleanup frees the same allocation twice. The condition is reachable only when a consuming application parses untrusted YANG input, producing heap corruption that crashes the process and can enable code execution.

The record

CVE
CVE-2019-20394
Published
Jan 22, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-415, CWE-416, T1204.002, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 22, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.0Red HatCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-415Double Free
CWE-416Use After Free
T1204.002Malicious File
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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