CVE-2024-45993: Giflib Project Giflib Buffer Overflow

CVE-2024-45993 Overview

CVE-2024-45993 is a heap buffer overflow vulnerability in Giflib version 5.2.2, specifically in the gif2rgb utility. Giflib is a widely used C library for reading and writing GIF images, and gif2rgb is a conversion tool bundled with the project. An attacker can craft a malicious GIF file that triggers an out-of-bounds write on the heap when processed by gif2rgb. The flaw is categorized under [CWE-787] Out-of-Bounds Write and [CWE-122] Heap-Based Buffer Overflow. Successful exploitation may corrupt heap memory, causing process termination or altering adjacent data.

Critical Impact

Processing an attacker-supplied GIF file with gif2rgb can trigger heap corruption, leading to integrity and availability impact on the affected host.

Affected Products

• Giflib 5.2.2 (giflib_project:giflib:5.2.2)
• The gif2rgb utility shipped with Giflib
• Downstream applications and pipelines that invoke gif2rgb for GIF conversion

Discovery Timeline

• 2024-09-30 - CVE-2024-45993 published to the National Vulnerability Database (NVD)
• 2026-07-05 - Last updated in NVD database

Technical Details for CVE-2024-45993

Vulnerability Analysis

The vulnerability resides in the gif2rgb conversion utility distributed with Giflib 5.2.2. When gif2rgb parses a specially crafted GIF file, it writes data beyond the bounds of a heap-allocated buffer. Because GIF parsing derives buffer sizes from attacker-controlled header fields such as image width, height, and color table dimensions, malformed values can desynchronize allocation size from actual write length. The result is a heap-based buffer overflow that corrupts adjacent heap metadata or data structures.

The CVSS vector indicates the impact is limited to integrity and availability, with no confidentiality impact. In practical terms, the primary observed outcome is process crashes and heap corruption rather than direct code execution, though heap corruption in C libraries is often a precursor to further exploitation research.

Root Cause

The root cause is missing or insufficient bounds validation in the GIF decoding path used by gif2rgb. Fields parsed from the GIF file dictate write operations into heap buffers whose sizes are computed without adequate validation. This falls under [CWE-787] Out-of-Bounds Write combined with [CWE-122] Heap-Based Buffer Overflow.

Attack Vector

Exploitation requires an attacker to deliver a malicious GIF file to a system where gif2rgb processes untrusted input. Common delivery paths include automated image-processing pipelines, upload endpoints that invoke gif2rgb in the backend, and command-line workflows that batch-convert user-supplied GIFs. No authentication or user interaction is required by the vulnerable component itself. See the GitLab Project PoC Repository for proof-of-concept material.

// No verified exploit code is published in the enriched dataset.
// Refer to the linked PoC repository for technical details on
// crafting a GIF that triggers the heap overflow in gif2rgb.

Detection Methods for CVE-2024-45993

Indicators of Compromise

• Unexpected crashes, SIGABRT, or SIGSEGV signals emitted by the gif2rgb process during batch image processing
• Heap corruption diagnostics from glibc such as malloc(): corrupted top size or double free or corruption in application logs
• GIF files with anomalous header dimensions or logical screen descriptors inconsistent with actual image content

Detection Strategies

• Run gif2rgb and downstream consumers under AddressSanitizer (ASan) in test environments to surface heap out-of-bounds writes
• Inventory hosts and container images for Giflib 5.2.2 binaries and any statically linked copies of libgif
• Alert on process termination or non-zero exit codes from image-conversion workers handling user-uploaded content

Monitoring Recommendations

• Log all invocations of gif2rgb with the source and hash of the input file to support post-incident analysis
• Monitor for repeated crashes of image-processing services, which may indicate probing for the overflow
• Correlate file-upload telemetry with worker-process exit status to identify malicious GIF submissions

How to Mitigate CVE-2024-45993

Immediate Actions Required

• Restrict gif2rgb usage on untrusted input until an upstream patched release is deployed
• Sandbox image-conversion utilities using seccomp, containers, or dedicated low-privilege service accounts
• Validate GIF file headers and reject images with implausible dimensions or malformed logical screen descriptors before invoking gif2rgb

Patch Information

At the time of publication, no vendor advisory URL is listed in the enriched CVE data. Monitor the upstream Giflib project for a release beyond 5.2.2 that addresses the heap buffer overflow in gif2rgb, and track distribution security trackers for backported fixes.

Workarounds

• Replace gif2rgb in production pipelines with an alternative decoder that has been fuzz-hardened against malformed GIFs
• Enforce strict file-size and dimension caps on user-supplied GIFs at the ingress boundary
• Run image-conversion workloads inside isolated containers with read-only filesystems and no network egress

# Example: isolate gif2rgb execution with a restricted user and resource limits
sudo useradd -r -s /usr/sbin/nologin gifworker
sudo -u gifworker \
  systemd-run --scope \
    -p MemoryMax=256M \
    -p CPUQuota=50% \
    -p NoNewPrivileges=yes \
    -p PrivateNetwork=yes \
    gif2rgb -o /tmp/out.rgb /tmp/input.gif