What is the CVSS score of CVE-2026-21897?

CVE-2026-21897 has a CVSS 3.1 base score of 7.3 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L. EPSS exploitation probability: 0.0%.

Which versions of Cryptolib are affected by CVE-2026-21897?

CVE-2026-21897 presents moderate security risk, a out-of-bounds write vulnerability rated CVSS 7.3.

How to fix or mitigate CVE-2026-21897?

Within 7 days: Identify all affected systems and apply vendor patches promptly. If patching is delayed, consider network segmentation to limit exposure.

Cryptolib CVE-2026-21897

HIGH

Out-of-bounds Write (CWE-787)

2026-01-10 security-advisories@github.com

Buffer Overflow Cryptolib

7.3

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

7.3 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

Low

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

CVE Published

Jan 10, 2026 - 01:16 nvd

HIGH 7.3

DescriptionGitHub 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, 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.

AnalysisAI

Out-of-bounds write in CryptoLib's SDLS-EP implementation allows unauthenticated network attackers to corrupt the gvcid_counter variable by writing beyond array bounds during parameter registration, potentially disrupting spacecraft-to-ground station communications security. Affected systems running CryptoLib versions prior to 1.4.3 are vulnerable to manipulation of parameter lookup logic without authentication or user interaction. No patch is currently available for this vulnerability affecting NASA's core Flight System deployments.

Technical ContextAI

Classified as CWE-787 (Out-of-bounds Write). Affects 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, 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 imm