CVE-2025-59534: NASA CryptoLib RCE Vulnerability

CVE-2025-59534 Overview

CVE-2025-59534 is a command injection vulnerability in NASA CryptoLib, a software-only implementation of the CCSDS Space Data Link Security Protocol - Extended Procedures (SDLS-EP). The library secures communications between spacecraft running the core Flight System (cFS) and ground stations. The flaw resides in the initialize_kerberos_keytab_file_login() function, which interpolates user-controlled input directly into a shell command and executes it via system() without sanitization or validation. An attacker who controls the username or keytab path input can execute arbitrary operating system commands in the context of the CryptoLib process. The issue was patched in version 1.4.2.

Critical Impact
Successful exploitation of CVE-2025-59534 allows arbitrary command execution on systems running vulnerable CryptoLib builds, compromising the confidentiality, integrity, and availability of ground-station processes that handle spacecraft cryptographic operations.

Affected Products

NASA CryptoLib versions prior to 1.4.2
Deployments using the Cryptographic Authentication Manager (CAM) Kerberos keytab login path
Ground-station and cFS integrations consuming the vulnerable initialize_kerberos_keytab_file_login() routine

Discovery Timeline

2025-09-23 - CVE-2025-59534 published to NVD
2025-10-08 - Last updated in NVD database

Technical Details for CVE-2025-59534

Vulnerability Analysis

The vulnerability is classified as OS Command Injection [CWE-78]. The function initialize_kerberos_keytab_file_login() constructs a shell command using user-supplied username and keytab path values and passes the resulting string to system(). Because the inputs are not validated against an allow-list of safe characters, an attacker can embed shell metacharacters such as ;, &&, |, or backticks to break out of the intended command and execute arbitrary code. The attack requires local access and user interaction, consistent with a workflow where an operator triggers Kerberos initialization with attacker-influenced configuration values. Execution occurs with the privileges of the host process, which in operational ground systems may include privileged access to spacecraft command-and-control interfaces.

Root Cause

The root cause is unsafe construction of a shell command from untrusted input combined with use of system(), which spawns /bin/sh -c and interprets shell metacharacters. CryptoLib did not enforce input validation on the username or path strings before interpolation.

Attack Vector

An attacker supplies a crafted username or keytab path containing shell metacharacters through a configuration file, environment value, or interactive prompt consumed by the Kerberos initialization flow. When initialize_kerberos_keytab_file_login() is invoked, the injected payload is executed by the shell.

// Security patch in src/core/crypto.c
// Adds character allow-lists and supports removal of the system() call
int32_t is_safe_username(const char *s)
{
    for (const unsigned char *p = (const unsigned char *)s; *p; ++p) {
        if (!(isalnum(*p) || *p == '.' || *p == '_' || *p == '-'))
            return CRYPTO_LIB_ERROR;
    }
    return CRYPTO_LIB_SUCCESS;
}

int32_t is_safe_path(const char *s)
{
    for (const unsigned char *p = (const unsigned char *)s; *p; ++p) {
        if (!(isalnum(*p) || *p == '.' || *p == '_' || *p == '-' || *p == '/'))
            return CRYPTO_LIB_ERROR;
    }
    return CRYPTO_LIB_SUCCESS;
}
// Source: https://github.com/nasa/CryptoLib/commit/3ccb1b306026bb20a028fbfdcf18935f7345ed2f

Detection Methods for CVE-2025-59534

Indicators of Compromise

Unexpected child processes of the CryptoLib host binary, particularly /bin/sh -c invocations spawned from the Kerberos initialization path
Configuration files or environment variables containing shell metacharacters (;, &&, |, backticks, $()) in username or keytab path fields
Anomalous outbound network connections initiated immediately after Kerberos keytab login routines run

Detection Strategies

Audit process-execution telemetry for system()-style shell invocations originating from CryptoLib-linked processes
Inspect application and shell history logs for username or path values that contain non-alphanumeric characters outside ., _, -, and /
Compare deployed CryptoLib binaries and source trees against version 1.4.2 to identify vulnerable builds

Monitoring Recommendations

Enable shell command auditing (for example, auditd rules on execve) on ground-station hosts running CryptoLib
Forward process lineage and command-line arguments to a centralized analytics platform for correlation
Alert on any execution of binaries such as wget, curl, nc, or bash parented by the CryptoLib process

How to Mitigate CVE-2025-59534

Immediate Actions Required

Upgrade NASA CryptoLib to version 1.4.2 or later on all ground-station and cFS-integrated systems
Inventory configuration files supplying username and keytab path values, and remove any entries containing shell metacharacters
Restrict local access to hosts running CryptoLib to authorized operators only

Patch Information

The fix is published in the upstream commit NASA CryptoLib commit 3ccb1b3 and described in the GitHub Security Advisory GHSA-jw5c-58hr-m3v3. The patch removes the system() invocation and introduces is_safe_username() and is_safe_path() allow-list validators that reject any character outside alphanumerics, ., _, -, and /.

Workarounds

Where immediate upgrade is not possible, disable the Kerberos keytab login code path in CryptoLib configuration
Constrain username and keytab path inputs to alphanumeric characters using an external wrapper or validation script
Run CryptoLib under a dedicated, least-privileged service account to limit the blast radius of command injection

bash

# Verify the installed CryptoLib version and update to the patched release
git -C CryptoLib fetch --tags
git -C CryptoLib checkout v1.4.2
cmake -S CryptoLib -B CryptoLib/build && cmake --build CryptoLib/build