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Vulnerability record · CVE-2026-21900 · published 10 January 2026

CVE-2026-21900: Nasa cryptolib out-of-bounds read vulnerability

NNasa · 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 when processing short or malformed metadata strings. This issue has been patched in version 1.4.3.

8.2 CVSS 4.0 High EPSS 0.59% · top 54.2% CWE-125 · Out-of-bounds read
8.2CVSS 4.0 base score
0.59%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

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.

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:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/nasa/CryptoLib/commit/2372efd3da1ccb226b4297222e25f41ecc84821d Patch
https://github.com/nasa/CryptoLib/releases/tag/v1.4.3 Release Notes
https://github.com/nasa/CryptoLib/security/advisories/GHSA-4g6v-36fv-qcvw ExploitVendor Advisory
https://github.com/nasa/CryptoLib/security/advisories/GHSA-4g6v-36fv-qcvw ExploitVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.9CVE-2025-46673Nasa cryptolib improper control of dynamically-managed code vulnerabilityNASA CryptoLib before 1.3.2 does not check whether the SA is in an operational state before use, possibly leading to a bypass of the Space Data Link …EPSS 0.50%9.9CVE-2025-46674Nasa cryptolib vulnerabilityNASA CryptoLib before 1.3.2 uses Extended Procedures that are a Work in Progress (not intended for use during flight), potentially leading to a keyst…EPSS 0.60%9.3CVE-2025-30356Nasa cryptolib out-of-bounds write vulnerabilityCryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communication…EPSS 0.65%9.1CVE-2025-30216Nasa cryptolib heap-based buffer overflow vulnerabilityCryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communication…EPSS 2.7%8.9CVE-2025-29911Nasa cryptolib heap-based buffer overflow vulnerabilityCryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communication…EPSS 0.74%8.9CVE-2025-29912Nasa cryptolib heap-based buffer overflow vulnerabilityCryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communication…EPSS 1.1%8.9CVE-2025-29913Nasa cryptolib out-of-bounds read vulnerabilityCryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communication…EPSS 0.72%8.9CVE-2025-29909Nasa cryptolib out-of-bounds write vulnerabilityCryptoLib provides a software-only solution using the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP) to secure communication…EPSS 1.1%

Source: NIST National Vulnerability Database (record CVE-2026-21900), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.