CVE-2026-8916: Samsung rlottie Buffer Overflow Vulnerability

CVE-2026-8916 Overview

CVE-2026-8916 is an out-of-bounds write vulnerability [CWE-787] in Samsung Open Source rlottie, a library used to render Lottie animations. The flaw allows attackers to overflow buffers when the library parses a crafted animation file. Exploitation requires local access and user interaction, such as opening a malicious animation in an application that embeds rlottie. The defect is fixed in commit dcfde72eae1b0464dc0dd760aec00ada6a148635; all earlier versions are affected.

Critical Impact

Successful exploitation can corrupt process memory, crash applications, and may enable arbitrary code execution within the host process consuming rlottie-rendered content.

Affected Products

• Samsung Open Source rlottie library, all versions prior to commit dcfde72eae1b0464dc0dd760aec00ada6a148635
• Applications and platforms that statically or dynamically link vulnerable rlottie builds
• Downstream projects bundling rlottie for Lottie animation rendering

Discovery Timeline

• 2026-06-04 - CVE-2026-8916 published to NVD
• 2026-06-04 - Last updated in NVD database

Technical Details for CVE-2026-8916

Vulnerability Analysis

The vulnerability is an out-of-bounds write in the rlottie parser. rlottie deserializes JSON-based Lottie animation descriptors and constructs in-memory representations of shapes, paths, and keyframes. When processing malformed or adversarially structured input, the library writes past the bounds of an allocated buffer.

The write primitive enables corruption of adjacent heap data. Depending on allocator state, attackers can overwrite object metadata, function pointers, or vtables consumed during subsequent rendering. The result is consistent crashes and, in favorable allocator layouts, controlled memory corruption.

The issue carries a CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H vector. The local attack vector and required user interaction reflect that a victim must open or render a crafted file in a host application.

Root Cause

The root cause is missing or inadequate bounds enforcement during buffer population while parsing Lottie animation data. The corrective change in commit dcfde72eae1b0464dc0dd760aec00ada6a148635 adds the required validation. Refer to the GitHub Pull Request #589 for the precise code-level fix.

Attack Vector

An attacker crafts a malicious Lottie JSON file and delivers it through any application that uses rlottie to render animations. The victim must open the file or load content that triggers rendering. Because rlottie is embedded in chat clients, media viewers, and mobile applications, common delivery paths include messaging attachments, downloaded stickers, and web-loaded assets.

No synthetic exploit code is reproduced here. Technical details of the fix are available in the upstream patch.

Detection Methods for CVE-2026-8916

Indicators of Compromise

• Repeated crashes or segmentation faults in processes that load rlottie after opening animation files
• Unexpected heap corruption traces or ASan reports referencing rlottie parser symbols
• Inbound or stored Lottie JSON files with abnormally large arrays, malformed shape descriptors, or oversized keyframe definitions

Detection Strategies

• Inventory applications that statically link or bundle rlottie and compare versions against commit dcfde72eae1b0464dc0dd760aec00ada6a148635
• Enable AddressSanitizer or equivalent runtime checks in development and QA builds to catch out-of-bounds writes during Lottie parsing
• Scan file ingestion pipelines for Lottie payloads and validate JSON structure against schema constraints before rendering

Monitoring Recommendations

• Forward application crash telemetry from endpoints to centralized logging for correlation across users opening similar files
• Monitor messaging and content delivery platforms for Lottie attachments originating from untrusted senders
• Alert on child process termination patterns consistent with parser memory corruption in applications that embed rlottie

How to Mitigate CVE-2026-8916

Immediate Actions Required

• Update rlottie to a build that includes commit dcfde72eae1b0464dc0dd760aec00ada6a148635 or later
• Rebuild and redistribute any in-house applications that statically link rlottie
• Restrict opening of untrusted Lottie animation files until patched binaries are deployed

Patch Information

The upstream fix is merged in commit dcfde72eae1b0464dc0dd760aec00ada6a148635. Consumers must pull this commit, or any tagged release that contains it, and recompile dependent applications. Review the GitHub Pull Request #589 for the full patch context and changed files.

Workarounds

• Disable Lottie animation rendering in affected applications until the patched library is integrated
• Filter Lottie files at email and messaging gateways when the source cannot be validated
• Sandbox the rendering process to limit the impact of memory corruption on the host system

# Verify the rlottie source tree includes the fix commit
cd rlottie
git fetch origin
git merge-base --is-ancestor dcfde72eae1b0464dc0dd760aec00ada6a148635 HEAD \
  && echo "Patched" || echo "Vulnerable - update required"