Cryptolib
CVE-2026-21900
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A06:2021 - Vulnerable and Outdated Components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 5.9 (MEDIUM). Attack vector: Network. Complexity: High. Privileges required: None. User interaction: None. Public exploit/POC available. |
| Exploit ScenarioDerived | An attacker could exploit this vulnerability to compromise the affected system. |
Get an e-mail when this CVE is exploited, patched or re-scored. Free account.
Alert meAnalysisAIv1 – Mar 12, 2026
CryptoLib versions prior to 1.4.3 suffer from an out-of-bounds heap read in the cryptography_encrypt() function when processing malformed JSON metadata from KMC servers, allowing remote attackers to trigger a denial of service condition. The vulnerability stems from improper buffer boundary checking during string parsing in spacecraft-ground station communications secured by the SDLS-EP protocol. Public exploit code exists for this medium-severity flaw, though a patch is 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 5.9 MEDIUM]
RemediationAI
A vendor patch is available — apply it immediately. Fixed in version 1.4.3.. Restrict network access to the affected service where possible.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
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, 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
Know when Cryptolib gets its next vulnerability
- Watch products and get an email when something new is published
- Check this CVE against your own stack and servers
- Exploit and PoC references, threat intelligence from 22 sources
No credit card · 7-day full trial
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
Lifecycle Timeline
3DescriptionGitHub 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, 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.
Executive ViewAI
CVE-2026-21900 presents moderate security risk, a out-of-bounds read vulnerability rated CVSS 5.9. Exploitation could cause memory corruption or application crashes. Proof-of-concept code is publicly available. A patch is available and should be applied during regular vulnerability management.
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
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
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