Cyber Resilience

CVE-2021-28903

HighPublic PoCDDoS

Published: 20 May 2021

Published
20 May 2021
Modified
21 November 2024
KEV Added
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Patch
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CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0046 64.4th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-28903 is a high-severity Uncontrolled Recursion (CWE-674) vulnerability in Cesnet Libyang. Its CVSS base score is 7.5 (High).

Operationally, ranked in the top 35.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

A stack overflow in libyang <= v1.0.225 can cause a denial of service through function lyxml_parse_mem(). lyxml_parse_elem() function will be called recursively, which will consume stack space and lead to crash.

CWE(s)
CWE-674

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

cesnet
libyang
≤ 1.0.225

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CP-7 Alternate Processing Site
addresses: CWE-674

Supports resumption at alternate site when uncontrolled recursion causes primary site failure or crash.

SC-5 Denial-of-service Protection
addresses: CWE-674

Prevents uncontrolled recursion that exhausts stack or CPU resources.

References