Cryptolib
CVE-2026-21900
MEDIUM
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
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
4DescriptionGitHub 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.
AnalysisAI
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. …
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Vulnerability AssessmentAI
| Risk Assessment | CVSS 5.9 (MEDIUM). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker could exploit this vulnerability to compromise the affected system. |
| Remediation | A vendor patch is available — apply it immediately. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. …
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