CVE-2017-5209

Out-of-bounds Read in The base64decode function in base64

Verified by Precogs Threat Research
Last Updated: Apr 20, 2025
Base Score
9.1CRITICAL

Executive Summary

CVE-2017-5209 is a critical severity vulnerability affecting binary-analysis. It is classified as Out-of-bounds Read. Ensure your systems and dependencies are patched immediately to mitigate exposure risks.

Precogs AI Insight

"A buffer overflow exists in the `base64decode` function in specific base64 parsing implementations. Attackers provide an excessively long or malformed base64 encoded string to overflow a stack or heap buffer, executing arbitrary code. Precogs Binary SAST uncovers missing bounds checks in data decoding routines."

Exploit Probability (EPSS)
Low (0.4%)
Public POC
Available
Exploit Probability
High (84%)
Public POC
Available
Affected Assets
binary analysisCWE-125

What is this vulnerability?

CVE-2017-5209 is categorized as a critical Out-of-bounds Read flaw with a CVSS base score of 9.1. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

The base64decode function in base64.c in libimobiledevice libplist through 1.12 allows attackers to obtain sensitive information from process memory or cause a denial of service (buffer over-read) via split encoded Apple Property List data.

This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.

Risk Assessment

MetricValue
CVSS Base Score9.1 (CRITICAL)
Vector StringCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
PublishedJanuary 11, 2017
Last ModifiedApril 20, 2025
Related CWEsCWE-125

Impact on Systems

Remote Code Execution: Attackers can overwrite the instruction pointer to redirect execution to malicious shellcode.

Memory Corruption: Overwriting adjacent memory regions can corrupt critical application state, leading to privilege escalation.

Denial of Service: Triggering segmentation faults results in immediate disruption of critical systems.

How to Fix and Mitigate CVE-2017-5209

  1. Apply Vendor Patches: Upgrade affected components to their latest, non-vulnerable versions immediately.
  2. Implement Input Validation: Ensure all user-supplied data is validated, sanitized, and type-checked before processing.
  3. Deploy Runtime Protection: Use Precogs continuous monitoring to detect exploitation attempts in real time.
  4. Audit Dependencies: Review and update all third-party libraries and transitive dependencies.

Defending with Precogs AI

A buffer overflow exists in the base64decode function in specific base64 parsing implementations. Attackers provide an excessively long or malformed base64 encoded string to overflow a stack or heap buffer, executing arbitrary code. Precogs Binary SAST uncovers missing bounds checks in data decoding routines.

Use Precogs to continuously scan your codebase, binaries, APIs, and infrastructure for this vulnerability class and related attack patterns. Our AI-powered detection engine combines static analysis with threat intelligence to identify exploitable weaknesses before attackers do.

Start scanning with Precogs →

Vulnerability Code Signature

Attack Data Flow

StageDetail
SourceNetwork packet or file input
VectorRead operation extends beyond the allocated buffer bounds
Sinkmemcpy(), strlen(), or pointer arithmetic
ImpactInformation disclosure, memory leak, denial of service

Vulnerable Code Pattern

// ❌ VULNERABLE: Out-of-bounds read
void read_data(char *input, int length) {
    char buffer[64] = {0};
    // Taint sink: reads beyond buffer size if length > 64
    memcpy(buffer, input, length);
}

Secure Code Pattern

// ✅ SECURE: Bounded read
void read_data(char *input, int length) {
    char buffer[64] = {0};
    // Sanitized boundary check
    int safe_length = (length > sizeof(buffer)) ? sizeof(buffer) : length;
    memcpy(buffer, input, safe_length);
}

How Precogs Detects This

Precogs Binary SAST engine explicitly uncovers memory boundary violations and unsafe memory management functions in compiled binaries.\n

Related Vulnerabilitiesvia CWE-125

Is your system affected?

Precogs AI detects CVE-2017-5209 in compiled binaries, LLMs, and application layers — even without source code access.