CVE-2026-30141: AnimatedGIF Library RCE Vulnerability

CVE-2026-30141 Overview

CVE-2026-30141 is a buffer overflow vulnerability in bitbank2 AnimatedGIF v2.2.0, an open-source GIF decoding library. The flaw resides in the DecodeLZW function, which processes Lempel-Ziv-Welch (LZW) compressed data within GIF files. Remote attackers can exploit this issue by delivering a crafted GIF file to a vulnerable application. Successful exploitation causes a denial of service through application crash or potentially enables arbitrary code execution. The vulnerability is tracked under [CWE-120] (Buffer Copy without Checking Size of Input).

Critical Impact
Remote attackers can trigger memory corruption in the DecodeLZW routine through a malicious GIF file, leading to crashes or arbitrary code execution without authentication or user interaction.

Affected Products

bitbank2 AnimatedGIF v2.2.0
Applications and firmware embedding the AnimatedGIF library for GIF rendering
Embedded and IoT devices that integrate AnimatedGIF for display output

Discovery Timeline

2026-06-09 - CVE-2026-30141 published to NVD
2026-06-10 - Last updated in NVD database

Technical Details for CVE-2026-30141

Vulnerability Analysis

The vulnerability is a classic buffer overflow inside the DecodeLZW function of the AnimatedGIF library. AnimatedGIF parses and renders GIF89a animations, decoding LZW-compressed pixel data into an output buffer. When the decoder processes attacker-controlled LZW codes, it fails to validate that decoded data fits within the destination buffer. Writing past the buffer corrupts adjacent memory structures, including return addresses, function pointers, or heap metadata depending on allocation context.

Because the AnimatedGIF library targets embedded platforms and microcontrollers, exploitation impact varies by host. Larger applications using the library may experience process crashes, while constrained devices can suffer firmware-level memory corruption.

Root Cause

The root cause is missing bounds enforcement in DecodeLZW when expanding LZW dictionary entries. The decoder trusts code lengths and dictionary references embedded in the GIF stream. A crafted file can declare oversized or recursive dictionary entries that exceed the fixed output buffer. The library does not verify that the cumulative decoded length remains within allocated boundaries before writing, satisfying the conditions for [CWE-120].

Attack Vector

The attack is remote and requires no authentication or user interaction beyond loading a malicious GIF. An attacker hosts or transmits a specially crafted GIF file to any application or device that decodes GIF content using AnimatedGIF. Examples include image viewers, IoT display firmware, ESP32-based projects, and chat or messaging clients that auto-render received images. Triggering the decoder is sufficient to invoke the vulnerable code path.

No public proof-of-concept is currently linked in the advisory. Technical details remain under discussion in the GitHub Issue Discussion.

Detection Methods for CVE-2026-30141

Indicators of Compromise

Unexpected process termination or watchdog resets on devices that recently rendered GIF content.
Crash dumps referencing the DecodeLZW function or related symbols within the AnimatedGIF library.
Inbound network traffic delivering GIF files from untrusted sources to endpoints that embed AnimatedGIF.
Heap or stack corruption signatures captured by runtime memory protection logs.

Detection Strategies

Perform software composition analysis (SCA) across firmware images and application dependencies to locate AnimatedGIF v2.2.0.
Inspect GIF files at network boundaries for malformed LZW headers, oversized code tables, or anomalous logical screen descriptors.
Enable Address Sanitizer (ASan) or equivalent instrumentation during testing of applications that link AnimatedGIF.
Hunt for repeated decoder crashes correlated with image rendering processes in endpoint telemetry.

Monitoring Recommendations

Centralize crash and exception telemetry from endpoints, mobile clients, and embedded devices to identify decoder failures.
Monitor outbound connections from devices following GIF-rendering events to detect post-exploitation callbacks.
Alert on unusual writes to memory regions adjacent to image decoding buffers when runtime protections are available.

How to Mitigate CVE-2026-30141

Immediate Actions Required

Inventory all applications, firmware, and embedded projects that statically or dynamically link bitbank2 AnimatedGIF v2.2.0.
Restrict ingestion of GIF files from untrusted sources until a patched library version is deployed.
Disable or sandbox automatic GIF rendering features in messaging and display applications where feasible.
Track the upstream GitHub Issue Discussion for fix status and rebuild dependent firmware once a patched release is published.

Patch Information

No official patched release is referenced in the current advisory. Maintain awareness through the upstream AnimatedGIF repository and rebuild downstream products after a fix is merged. Vendors shipping firmware containing the library should plan a coordinated update cycle once the patch lands.

Workarounds

Pre-validate GIF inputs with a hardened parser that enforces strict LZW code-size and dictionary-length limits before passing data to AnimatedGIF.
Run GIF decoding within an isolated process, sandbox, or memory-protected task so that corruption cannot impact the broader application.
Enforce stack canaries, non-executable memory, and address space layout randomization (ASLR) in builds that consume the library.
Block or strip GIF attachments at email and web proxies for high-risk environments until remediation is available.

bash

# Configuration example: identify AnimatedGIF usage in source trees
grep -RIn "AnimatedGIF" ./src ./lib
grep -RIn "DecodeLZW" ./src ./lib