CVE-2026-21900: CryptoLib Has Out-of-Bounds Read in KMC Encrypt Metadata Parsing via Flawed strtok Pattern

Published Jan 10, 2026
·
Updated

CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communications between a spacecraft running the core Flight System (cFS) and a ground station. Prior to version 1.4.3, an out-of-bounds heap read vulnerability in cryptographyencrypt() occurs when parsing JSON metadata from KMC server responses. The flawed strtok iteration pattern uses ptr + strlen(ptr) + 1 which reads one byte past allocated buffer boundaries when processing short or malformed metadata strings. This issue has been patched in version 1.4.3.

Affected Software

2 affected components
CryptoLib CryptoLib<1.4.3
nasa CryptoLib<1.4.3

Event History

Jan 10, 2026
CVE Published
via MITRE·12:14 AM
Data Sourced
via MITRE·12:14 AM
DescriptionWeakness
Data Sourced
via NVD·01:16 AM
RemedyDescriptionSeverityWeaknessAffected Software
Aug 29, 58046
Event
via FIRST·04:31 AM
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Frequently Asked Questions

1

What is the severity of CVE-2026-21900?

CVE-2026-21900 has been classified as a moderate severity vulnerability due to its potential to cause an out-of-bounds heap read.

2

How do I fix CVE-2026-21900?

To fix CVE-2026-21900, upgrade CryptoLib to version 1.4.3 or later.

3

What versions of CryptoLib are affected by CVE-2026-21900?

CVE-2026-21900 affects all versions of CryptoLib prior to version 1.4.3.

4

What type of vulnerability is CVE-2026-21900?

CVE-2026-21900 is categorized as a heap-related vulnerability that involves an out-of-bounds read.

5

What is the potential impact of CVE-2026-21900?

The potential impact of CVE-2026-21900 includes unauthorized access to sensitive data and possible denial of service.

Contact

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