Unrated severityOSV Advisory· Published Jan 10, 2026· Updated Jan 13, 2026
CryptoLib Has Out-of-Bounds Read in KMC Encrypt Metadata Parsing via Flawed strtok Pattern
CVE-2026-21900
Description
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 cryptography_encrypt() 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.
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Affected products
2Patches
Vulnerability mechanics
References
3- github.com/nasa/CryptoLib/commit/2372efd3da1ccb226b4297222e25f41ecc84821dmitrex_refsource_MISC
- github.com/nasa/CryptoLib/releases/tag/v1.4.3mitrex_refsource_MISC
- github.com/nasa/CryptoLib/security/advisories/GHSA-4g6v-36fv-qcvwmitrex_refsource_CONFIRM
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