A double-free is present in libyang before v1.0-r1 in the function yyparse() when an empty description is used.
A double-free is present in libyang before v1.0-r1 in the function yyparse() when an empty description is used. Applications that use libyang to parse untrusted input yang files may be vulnerable to this flaw, which would cause a crash or potentially code execution.
- Published
- Jan 22, 2020
- Updated
- Jun 16, 2026
- EPSS
- 2.8% · 86th percentile
- CWE
- CWE-415
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Report tools
Action score
36
Monitor
Low priority for now.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.8%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| cesnet | libyang | cpe:2.3:a:cesnet:libyang |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cesnet libyang0.11
- cesnet libyang0.12
- cesnet libyang0.13
- cesnet libyang0.14
- cesnet libyang0.15
- cesnet libyang0.16
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:10 | libyang | before 0.16.105+really1.0-0+deb10u1 | 0.16.105+really1.0-0+deb10u1 |
| Debian:13 | libyang | before 1.0.176-1 | 1.0.176-1 |
| Red Hat:enterprise_linux:8::appstream | libyang | before 0:1.0.184-1.el8 | 0:1.0.184-1.el8 |
| Red Hat:enterprise_linux:8::appstream | libyang-cpp-debuginfo | before 0:1.0.184-1.el8 | 0:1.0.184-1.el8 |
| Red Hat:enterprise_linux:8::appstream | libyang-debuginfo | before 0:1.0.184-1.el8 | 0:1.0.184-1.el8 |
| Red Hat:enterprise_linux:8::appstream | libyang-debugsource | before 0:1.0.184-1.el8 | 0:1.0.184-1.el8 |
| Red Hat:enterprise_linux:8::appstream | python3-libyang-debuginfo | before 0:1.0.184-1.el8 | 0:1.0.184-1.el8 |
Same product
cesnet: all recordsOther highest-scoring records for the same primary product.
- CVE-2019-19334In all versions of libyang before 1.0-r5, a stack-based buffer overflow was discovered in the way libyang parses YANG files with a leaf of t40Plan
- CVE-2019-19333In all versions of libyang before 1.0-r5, a stack-based buffer overflow was discovered in the way libyang parses YANG files with a leaf of t40Plan
- CVE-2019-20397A double-free is present in libyang before v1.0-r1 in the function yyparse() when an organization field is not terminated.36Monitor
- CVE-2019-20394A double-free is present in libyang before v1.0-r3 in the function yyparse() when a type statement in used in a notification statement.36Monitor
- CVE-2021-28903A stack overflow in libyang <= v1.0.225 can cause a denial of service through function lyxml_parse_mem().31Monitor
- CVE-2026-44673libyang: lyb_read_string() integer overflow → heap buffer overflow30Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:libyang | 1.0.176-1 · Debian:13 | Package registry (OSV) |
| red hat:libyang | 0:1.0.184-1.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:libyang-cpp-debuginfo | 0:1.0.184-1.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:libyang-debuginfo | 0:1.0.184-1.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:libyang-debugsource | 0:1.0.184-1.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:python3-libyang-debuginfo | 0:1.0.184-1.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-415 · Double FreeCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- bugzilla.redhat.com/show_bug.cgi?id=1793930
- github.com/CESNET/libyang/commit/d9feacc4a590d35dbc1af21caf9080008b4450ed
- github.com/CESNET/libyang/compare/v0.16-r3...v1.0-r1
- lists.debian.org/debian-lts-announce/2023/09/msg00019.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.