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CVE-2026-21899 - CryptoLib Plugin

CVE-2026-21899

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.

CVE-2026-21899

MEDIUM CVSS 4.7 Published 2026-01-10 Updated 2026-01-15
AI Risk Moderate (52/100) Active Exploit: No strong signal Published Exploit: Public exploit references found Priority: P4 Planned
Severity Band MEDIUM
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
Affected Components 1
Reference Links 2
AI Risk Engine Moderate (52/100)
Exploitability Medium
Active Exploitation No strong signal
Published Exploit Status Public exploit references found

Threat Timeline

  1. 2026-01-10 CVE published and first recorded in the threat feed.
  2. 2026-01-15 Record updated with latest vulnerability metadata.
  3. 2026-04-09 AI technical context refreshed for mitigation and impact guidance.
  4. Now Monitoring for follow-up changes, linked references, and new related CVEs.

AI Context

Machine-generated threat intelligence

AI Updated 12 days ago

AI enriched 12 days ago (2026-04-09 07:10 UTC)

Technical Summary

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…

Potential Impact

Severity is MEDIUM (CVSS 4.7). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.

Exploitability Assessment

Exploitability is assessed as Medium based on published exploit references.

Primary risk drivers: published exploit references

Mitigation Recommendations

Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.

Detection & Monitoring

Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.

Business Impact Lens

Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

Affected Products

CryptoLib PLUGIN · cryptolib Affected: >= 1.4.3, <= 1.4.3 Fixed version not specified
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