What is the CVSS score of CVE-2026-21898?

CVE-2026-21898 has a CVSS 3.1 base score of 8.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H. EPSS exploitation probability: 0.0%.

Is there a public PoC exploit available for CVE-2026-21898?

Yes, a public proof-of-concept exploit is available for CVE-2026-21898. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2026-21898?

Within 7 days: Identify all affected systems and apply vendor patches promptly. Monitor vendor channels for patch availability.

Cryptolib CVE-2026-21898

HIGH

Out-of-bounds Read (CWE-125)

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

Buffer Overflow Information Disclosure Cryptolib Nasa

8.2

CVSS 3.1 · GitHub Advisory

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Send malformed AOS frame to spacecraft
Exploit

Parser reads unbounded memory in hash field
Impact

Information disclosure and denial of service triggered

Vulnerability Assessment

Weakness	CWE CWE-125 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, read limits MITRE ATT&CK 1 technique across 1 tactic: Collection The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	CryptoLib versions prior to 1.4.3 with SDLS-EP protocol enabled on spacecraft cFS receiving AOS frames from ground station. No authentication required; network-accessible space-ground link interface.
Impact	CVSS 8.2 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Public exploit/POC available.
Exploit ScenarioDerived	An attacker could exploit this vulnerability to compromise the affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

CryptoLib versions prior to 1.4.3 contain an out-of-bounds read vulnerability in the Crypto_AOS_ProcessSecurity function that allows remote attackers to crash spacecraft communications systems when parsing malformed AOS frame hashes. Public exploit code exists for this vulnerability affecting cFS deployments that rely on SDLS-EP for spacecraft-to-ground station security. The vulnerability has high severity due to its denial of service impact on critical space communications infrastructure, and no patch is currently available.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 8.2

RemediationAI

Fixed in version 1.4.3.. Restrict network access to the affected service where possible.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Classified as CWE-125 (Out-of-bounds Read). 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_AOS_ProcessSecurity function reads memory without valid bounds checking when parsing AOS frame hashes. This issue has been patched in version 1.4.3.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 8.2 HIGH

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

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

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Lifecycle Timeline

PoC Detected

Jan 15, 2026 - 21:48 vuln.today

Public exploit code

CVE Published

Jan 10, 2026 - 01:16 nvd

HIGH 8.2

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_AOS_ProcessSecurity function reads memory without valid bounds checking when parsing AOS frame hashes. This issue has been patched in version 1.4.3.

Executive ViewAI

Why It Matters

CVE-2026-21898 presents notable security risk, a out-of-bounds read vulnerability rated CVSS 8.2. Successful exploitation could significantly impact the confidentiality, integrity, or availability of affected systems. Proof-of-concept code is publicly available, increasing the risk of exploitation. Organizations should apply vendor updates when available and consider compensating controls in the interim.

Business Impact: High

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score

0.0%

Top 92% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC Yes

EPSS 0.0%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Out-of-Cycle

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +41

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.