Security readout for executives and security teams
Plain-English summary
libyang had a high-severity memory corruption flaw before version 1.0-r5. If a system lets an attacker supply YANG files for parsing, a crafted file could crash the service or possibly allow code execution.
Executive priority
Prioritize patching internet-facing or externally fed systems that parse YANG content. Treat as high risk because the stated impact includes service disruption and possible code execution, even though exploitation evidence is not provided.
Technical view
CVE-2019-19333 is a CWE-121 stack-based buffer overflow in libyang parsing of YANG files containing a leaf of type "bits". The supplied CVSS v3.0 score is 8.1, with no privileges or user interaction required but high attack complexity.
Likely exposure
Exposure is likely limited to applications that use vulnerable libyang versions and parse untrusted YANG files. Systems with libyang installed but no attacker-controlled YANG parsing path have lower practical exposure.
Exploitation context
The source bundle does not show active exploitation, and KEV status is false. Sources state potential impact as denial of service or possible code execution, but do not provide evidence of weaponized exploitation.
Researcher notes
The key validation question is whether untrusted YANG reaches vulnerable parsing code. CVSS indicates network attack vector and severe confidentiality, integrity, and availability impact, but high attack complexity. The bundle names the fixing threshold as libyang 1.0-r5.
Mitigation direction
- Upgrade libyang to 1.0-r5 or a vendor-fixed package.
- Apply relevant Red Hat or Fedora security updates where applicable.
- Restrict or disable parsing of untrusted YANG files until patched.
- Check vendor guidance for product-specific remediation.
- Retest dependent applications after updating libyang.
Validation and detection
- Inventory systems and applications using libyang.
- Confirm installed libyang versions are 1.0-r5 or vendor-fixed builds.
- Identify any service path accepting user-supplied YANG files.
- Verify Red Hat or Fedora advisory packages are installed where used.
- Run non-offensive regression tests for YANG parsing functionality.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-121: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2019-19333 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 8.1 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.1HighVector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-19333CVE reference · x_refsource_CONFIRM
- https://github.com/CESNET/libyang/commit/f6d684ade99dd37b21babaa8a856f64faa1e2e0dCVE reference · x_refsource_CONFIRM
- FEDORA-2019-dfe0b42bc5CVE reference · vendor-advisory, x_refsource_FEDORA
- FEDORA-2019-9d83929ffaCVE reference · vendor-advisory, x_refsource_FEDORA
- RHSA-2019:4360CVE reference · vendor-advisory, x_refsource_REDHAT
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.