CVE-2026-21897: nasa cryptolib Out-of-bounds Write

Vulnerability summary

CVE-2026-21897 is a high (CVSS 7.3) Out-of-bounds Write vulnerability in nasa cryptolib. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 19.7% of scored vulnerabilities.

Timeline

1. 10-01-2026
   PublishedVulnerability first disclosed.
2. 12-01-2026
   Last modifiedVulnerability information updated.

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, the Crypto_Config_Add_Gvcid_Managed_Parameters function only checks whether gvcid_counter > GVCID_MAN_PARAM_SIZE. As a result, it allows up to the 251st entry, which causes a write past the end of the array, overwriting gvcid_counter located immediately after gvcid_managed_parameters_array[250]. This leads to an out-of-bounds write, and the overwritten gvcid_counter may become an arbitrary value, potentially affecting the parameter lookup/registration logic that relies on it. This issue has been patched in version 1.4.3.

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.