In function read_yin_leaf() in libyang <= v1.0.225, it doesn't check whether the value of retval->ext[r] is NULL.
In function read_yin_leaf() in libyang <= v1.0.225, it doesn't check whether the value of retval->ext[r] is NULL. In some cases, it can be NULL, which leads to the operation of retval->ext[r]->flags that results in a crash.
- Published
- May 20, 2021
- Updated
- Jun 16, 2026
- EPSS
- 1.6% · 75th percentile
- CWE
- CWE-252
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Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.6%
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; 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 helpAffected 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 libyangup to 1.0.225 inclusive
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:13 | libyang | before 3.4.2+dfsg-2 | 3.4.2+dfsg-2 |
| SUSE:Linux Enterprise Module for Server Applications 15 SP3 | libyang | before 1.0.184-150300.3.6.1 | 1.0.184-150300.3.6.1 |
| SUSE:Linux Enterprise Module for Server Applications 15 SP3 | libyang | before 1.0.184-150300.3.6.1 | 1.0.184-150300.3.6.1 |
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-2019-20393A double-free is present in libyang before v1.0-r1 in the function yyparse() when an empty description is used.36Monitor
- CVE-2021-28903A stack overflow in libyang <= v1.0.225 can cause a denial of service through function lyxml_parse_mem().31Monitor
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 | 3.4.2+dfsg-2 · Debian:13 | Package registry (OSV) |
| opensuse:libyang | 1.0.184-150300.3.6.1 · openSUSE:Leap 15.3 | Package registry (OSV) |
| suse:libyang | 1.0.184-150300.3.6.1 · SUSE:Linux Enterprise Module for Server Applications 15 SP3 | 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.
No commit or PR link among the references.
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.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-252 · Unchecked Return ValueCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.