Cryptolib
CVE-2026-21899
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, read limits
MITRE ATT&CK
1 technique across 1 tactic: Collection The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS 4.7 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: High. User interaction: None. Public exploit/POC available. |
| Exploit ScenarioDerived | An attacker could exploit this vulnerability to compromise the affected system. |
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Alert meAnalysisAIv1 – Mar 12, 2026
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. Public exploit code exists for this vulnerability, though no patch is currently available.
Earlier versions of this analysis (1)
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. [CVSS 4.7 MEDIUM]
RemediationAI
Fixed in version 1.4.3.. Restrict network access to the affected service where possible.
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Classified as CWE-125 (Out-of-bounds Read). Affects Cryptolib. 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 inpu
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
Lifecycle Timeline
2DescriptionGitHub Advisory
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.
Executive ViewAI
CVE-2026-21899 presents moderate security risk, a out-of-bounds read vulnerability rated CVSS 4.7. Exploitation could cause memory corruption or application crashes. Proof-of-concept code is publicly available. Organizations should apply vendor updates when available and monitor for exploitation.
Apply vendor patch. If patching is delayed: enable ASLR/DEP, apply network segmentation.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)GitHub Advisory
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDL
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDL
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDL
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDL
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDL
CryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDL
CryptoLib versions prior to 1.4.3 contain an out-of-bounds read vulnerability in the Crypto_AOS_ProcessSecurity function
Command injection in NASA CryptoLib before 1.4.2 lets an attacker who controls the CAM 'username' or 'keytab_file_path'
CryptoLib versions prior to 1.4.3 contain a heap buffer overflow in the KMC crypto service's Base64 decoder, where overs
CryptoLib versions prior to 1.4.3 are vulnerable to denial of service through unbounded memory allocation in the KMC cry
CryptoLib versions prior to 1.4.3 contain an out-of-bounds heap read in the cryptography_aead_encrypt() function, affect
NASA CryptoLib v1.3.0 was discovered to contain an Out-of-Bounds read via the AOS subsystem (crypto_aos.c). Rated high s
Exploit-DB