CVE-2026-21899
CryptoLib has an out-of-bounds read and crash vulnerability when decoding an empty Base64url string
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, 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.
CVSS Vector Breakdown
AV:NAttack VectorAC:LAttack ComplexityPR:HPrivileges RequiredUI:NUser InteractionS:UScopeC:LConfidentialityI:LIntegrityA:LAvailabilityWeaknesses
Affected Products
Attack Graph
Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.
Exploitability
MITRE ATT&CK
1 techniqueReferences
Timeline
Unlock Complete Vulnerability Intelligence
Get the full picture for CVE-2026-21899 and every CVE in our database. Create a free account — no credit card required.
Create Free Account