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CryptolibApplication · Nasa

CVE-2026-21897

HIGH · 7.3 CVSS v3.1 Published 2026-01-10
Fix available
A fix is available. Upgrade to 1.4.3 or later.
See remediation →
82/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

CryptoLib contains an off-by-one error in the Crypto_Config_Add_Gvcid_Managed_Parameters function where the boundary check only validates gvcid_counter > GVCID_MAN_PARAM_SIZE, allowing the 251st entry to be written past the end of gvcid_managed_parameters_array[250], corrupting the adjacent gvcid_counter variable and affecting subsequent lookup/registration logic.

MitigationUpgrade to CryptoLib version 1.4.3 or later, which contains the patch for the boundary check vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
CryptolibApplication
Affected:< 1.4.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify CryptoLib installation
    Locate the CryptoLib library in your environment - check for files named 'cryptolib', 'CryptoLib', or related shared objects/libraries. Search in common library directories or project dependencies.
    Affected if CryptoLib is not found in the environment, the system is not affected by this CVE.
  2. Determine installed CryptoLib version
    Inspect the CryptoLib library file or associated version metadata. Check library version strings, headers, or package management records that reference CryptoLib.
    Affected if The installed version is less than 1.4.3 (e.g., 1.4.2, 1.4.1, 1.4.0, or earlier), indicating the vulnerable version is in use.
  3. Verify Crypto_Config_Add_Gvcid_Managed_Parameters is called
    Review application source code or binary to determine if the function Crypto_Config_Add_Gvcid_Managed_Parameters is invoked. This function is used to configure GVCID managed parameters.
    Affected if The vulnerable function is not called in your codebase, the specific flaw cannot be triggered.
  4. Check number of GVCID entries configured
    Inspect the code that calls Crypto_Config_Add_Gvcid_Managed_Parameters or review configuration data to count how many GVCID entries are being registered. The array size is 250 elements.
    Affected if More than 250 GVCID entries are being configured, which would trigger the off-by-one write past array bounds.

Your environment is affected if you are using a CryptoLib version earlier than 1.4.3 and your application configures more than 250 GVCID entries via the Crypto_Config_Add_Gvcid_Managed_Parameters function.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.4.3 or later
Fixed in 1.4.3
Interim mitigation

Upgrade to CryptoLib version 1.4.3 or later, which contains the patch for the boundary check vulnerability.

Recommended fix High confidence

1.4.3

  1. Identify the current version of CryptoLib being used in the project by reviewing dependency manifests or library files
  2. Locate the CryptoLib dependency in the project's dependency management system (e.g., package manager, build system, or submodule configuration)
  3. Update the CryptoLib dependency to version 1.4.3 or later
  4. Rebuild and recompile the project to ensure the updated library is linked
  5. Verify the fix by testing the gvcid parameter registration functionality to confirm the out-of-bounds write vulnerability is resolved

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Cryptolib Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,190
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-21897 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data