CVE-2026-21899
MEDIUMCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
Lifecycle Timeline
3Description
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, in base64urlDecode, padding-stripping dereferences input[inputLen - 1] before checking that inputLen > 0 or that input != NULL. For inputLen == 0, this becomes an OOB read at input[-1], potentially crashing the process. If input == NULL and inputLen == 0, it dereferences NULL - 1. This issue has been patched in version 1.4.3.
Analysis
CryptoLib versions prior to 1.4.3 contain an out-of-bounds read vulnerability in the base64urlDecode function that dereferences memory before validating input parameters, potentially causing a denial of service in spacecraft communications secured by SDLS-EP. Affected systems running cFS with vulnerable CryptoLib versions could crash when processing malformed base64 input. …
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Remediation
Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.
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