Cyber Resilience

CVE-2026-21900

HighPublic PoC

Published: 10 January 2026

Published
10 January 2026
Modified
16 January 2026
KEV Added
—
Patch
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CVSS Score v4 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0051 39.7th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-21900 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Nasa Cryptolib. Its CVSS base score is 8.2 (High).

Operationally, ranked at the 39.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)
CWE-125

Related Threats

CVEs Like This One

CVE-2026-22023Same product: Nasa Cryptolib
CVE-2026-21898Same product: Nasa Cryptolib
CVE-2025-29913Same product: Nasa Cryptolib
CVE-2025-29909Same product: Nasa Cryptolib
CVE-2025-29910Same product: Nasa Cryptolib
CVE-2025-29911Same product: Nasa Cryptolib
CVE-2026-22697Same product: Nasa Cryptolib
CVE-2025-29912Same product: Nasa Cryptolib
CVE-2025-30216Same product: Nasa Cryptolib
CVE-2026-21897Same product: Nasa Cryptolib

Affected Assets

nasa
cryptolib
≤ 1.4.3

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References