CVE-2026-2246: AprilRobotics Apriltag Buffer Overflow

CVE-2026-2246 Overview

A memory corruption vulnerability has been identified in AprilRobotics apriltag up to version 3.4.5. The vulnerability exists within the apriltag_detector_detect function in the file apriltag.c. Improper handling of input data can lead to memory corruption when processing specially crafted image data. This vulnerability requires local access to exploit and has been publicly disclosed with a patch available.

Critical Impact

Local attackers can trigger memory corruption by manipulating input to the apriltag_detector_detect function, potentially causing application crashes or denial of service in robotics and computer vision applications that rely on the AprilTag library.

Affected Products

• AprilRobotics apriltag versions up to 3.4.5
• Applications and robotics systems using affected apriltag library versions
• Computer vision systems implementing AprilTag detection

Discovery Timeline

• 2026-02-09 - CVE-2026-2246 published to NVD
• 2026-02-09 - Last updated in NVD database

Technical Details for CVE-2026-2246

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the apriltag_detector_detect function within apriltag.c, where insufficient validation of input image dimensions allows for memory corruption scenarios. When the function receives images with dimensions smaller than expected minimums, the subsequent processing operations can access memory outside the intended buffer boundaries, leading to undefined behavior.

The vulnerability requires local access to exploit, meaning an attacker would need to be able to provide malicious input to an application using the vulnerable apriltag library. The exploit has been publicly disclosed, increasing the risk of exploitation in the wild.

Root Cause

The root cause of this vulnerability is missing input validation for image dimensions in the apriltag_detector_detect function. Prior to the patch, the function did not verify that input images met minimum size requirements before processing. When extremely small images (less than 6x6 pixels) were passed to the function, the detection algorithm would attempt operations that exceeded the bounds of the allocated image buffer, resulting in memory corruption.

Attack Vector

The attack vector requires local access to a system running an application that uses the vulnerable apriltag library. An attacker could exploit this vulnerability by:

1. Providing a crafted image with dimensions smaller than 6x6 pixels to an application using apriltag
2. The malicious image triggers the apriltag_detector_detect function without proper bounds checking
3. Memory corruption occurs during tag detection processing
4. This can result in denial of service through application crashes

The following patch was applied to fix this vulnerability by adding proper image dimension validation:

         return s;
     }
 
+    if (im_orig->width < 6 || im_orig->height < 6) {
+        zarray_t *s = zarray_create(sizeof(apriltag_detection_t*));
+        debug_print("Image too small (%d x %d)\n", im_orig->width, im_orig->height);
+        return s;
+    }
+
     if (td->wp == NULL || td->nthreads != workerpool_get_nthreads(td->wp)) {
         workerpool_destroy(td->wp);
         td->wp = workerpool_create(td->nthreads);

Source: GitHub Commit Details

Detection Methods for CVE-2026-2246

Indicators of Compromise

• Unexpected crashes in applications using apriltag library during image processing
• Memory access violations or segmentation faults in processes utilizing apriltag_detector_detect
• Application logs showing abnormal termination when processing unusually small image inputs
• Core dumps or crash reports referencing apriltag.c or related library functions

Detection Strategies

• Implement application monitoring to detect crashes or unexpected termination in processes using the apriltag library
• Review application logs for memory-related errors during tag detection operations
• Audit systems for apriltag library versions prior to the patched release
• Deploy runtime memory monitoring tools to detect out-of-bounds memory access patterns

Monitoring Recommendations

• Enable crash reporting and analysis for applications utilizing apriltag in production environments
• Monitor process health and stability metrics for robotics and computer vision applications
• Implement input validation logging to track image dimensions passed to apriltag functions
• Set up alerting for repeated application failures in systems relying on AprilTag detection

How to Mitigate CVE-2026-2246

Immediate Actions Required

• Update apriltag library to a version containing commit cfac2f5ce1ffe2de25967eb1ab80bc5d99fc1a61 or later
• Review and rebuild applications that statically link the apriltag library
• Implement input validation in application code to reject images smaller than 6x6 pixels before passing to apriltag
• Audit all systems using apriltag to inventory vulnerable deployments

Patch Information

A patch has been made available through the AprilRobotics apriltag repository. The fix is contained in commit cfac2f5ce1ffe2de25967eb1ab80bc5d99fc1a61. The patch adds proper validation to check that input images are at least 6x6 pixels before proceeding with detection operations. Organizations should update to the patched version as soon as possible.

For more details, see the GitHub Commit Details and the GitHub Issue Tracking.

Workarounds

• Add application-level input validation to ensure all images passed to apriltag meet minimum dimension requirements (width >= 6, height >= 6)
• Implement wrapper functions around apriltag_detector_detect that validate image dimensions before calling the vulnerable function
• Consider sandboxing or isolating processes that utilize the apriltag library to limit impact of potential exploitation
• Temporarily disable apriltag functionality in non-critical systems until patching is complete

# Verify apriltag version and check for vulnerable installations
# Check if the patch commit is present in your apriltag installation
cd /path/to/apriltag
git log --oneline | grep cfac2f5

# If using package manager, check version
dpkg -l | grep apriltag
rpm -qa | grep apriltag

# Rebuild from source with patched version
git pull origin master
cmake -B build
cmake --build build
sudo cmake --install build