CVE-2026-102804: Nothings stb Library RCE Vulnerability

CVE-2026-102804 Overview

CVE-2026-102804 is an integer overflow vulnerability in the Nothings stb single-file public domain library, specifically within the hexwave_init function in stb_hexwave.h. The flaw affects code up to commit 2c980bb59875b0d32144a71867fbdebb2f77cd20. Attackers can trigger the overflow by manipulating the width or oversample arguments passed to the initialization function. The issue is classified under [CWE-189] Numeric Errors. A public proof-of-concept exists, and the maintainers have been notified through a GitHub issue but have not yet responded.

Critical Impact
Remote manipulation of the width and oversample parameters produces an integer overflow that can affect the integrity and availability of applications embedding stb_hexwave.h.

Affected Products

Nothings stb library, stb_hexwave.h component
Source revisions up to commit 2c980bb59875b0d32144a71867fbdebb2f77cd20
Downstream applications statically embedding the vulnerable header

Discovery Timeline

2026-09-30 - CVE-2026-102804 published to the National Vulnerability Database (NVD)
2026-09-30 - Last updated in NVD database

Technical Details for CVE-2026-102804

Vulnerability Analysis

The vulnerability resides in hexwave_init, an initialization routine exposed by the stb_hexwave.h header. The function accepts caller-supplied width and oversample integer arguments used in downstream size calculations. When either value is sufficiently large, arithmetic performed on these inputs wraps around the native integer range. The resulting truncated value is then used to size internal state, producing inconsistencies between allocated capacity and later read or write operations. Applications that expose the hexwave initializer to attacker-influenced input inherit the flaw. A working proof-of-concept, poc_hexwave.c, is attached to GitHub Issue #1961.

Root Cause

The root cause is missing bounds validation on the width and oversample parameters before they participate in size arithmetic inside hexwave_init. Because stb is a header-only library, each consumer statically compiles the vulnerable arithmetic. No sanity check rejects values that would overflow the destination type, allowing attacker-influenced values to corrupt subsequent buffer sizing.

Attack Vector

Exploitation requires that an application built against stb_hexwave.h pass untrusted input into hexwave_init. The advisory records the attack vector as network-reachable when the consuming application exposes hexwave configuration to remote inputs, for example through a media processing service or content pipeline. No authentication or user interaction is required for the underlying arithmetic flaw to trigger. Refer to the public proof-of-concept for parameter values that reproduce the condition.

No verified exploit code is reproduced here. See the VulDB entry for CVE-2026-102804 and the referenced PoC for technical specifics.

Detection Methods for CVE-2026-102804

Indicators of Compromise

Crashes or abnormal termination in processes that link stb_hexwave.h, particularly during audio or waveform initialization.
Unexpected memory allocation failures or heap corruption traces originating from hexwave_init call stacks.
Inbound requests containing unusually large width or oversample parameters directed at services that wrap the hexwave API.

Detection Strategies

Perform source-level auditing of dependencies for inclusion of stb_hexwave.h at or before commit 2c980bb59875b0d32144a71867fbdebb2f77cd20.
Add fuzzing coverage around hexwave_init using boundary-value inputs for the width and oversample arguments.
Enable AddressSanitizer or UndefinedBehaviorSanitizer in build pipelines to catch integer overflow and downstream memory issues during testing.

Monitoring Recommendations

Monitor application logs for repeated crashes tied to hexwave initialization or media parsing routines.
Alert on service restarts and worker respawns in processes that expose waveform generation to external inputs.
Track outbound telemetry from build systems that pull stb at unpinned revisions to identify vulnerable versions in production.

How to Mitigate CVE-2026-102804

Immediate Actions Required

Inventory all internal projects and third-party dependencies that vendor stb_hexwave.h and record the exact commit in use.
Validate width and oversample arguments at the application boundary, rejecting values that would overflow when multiplied with internal buffer sizes.
Restrict network exposure of any endpoint that forwards untrusted parameters into hexwave_init until validation is in place.

Patch Information

At the time of publication, the upstream project has not released a fix. Track the Nothings stb repository and GitHub Issue #1961 for maintainer response and patch commits. Consumers can apply local input validation as an interim measure.

Workarounds

Clamp width and oversample to conservative maximum values before invoking hexwave_init.
Wrap calls to hexwave_init in a validation shim that performs checked arithmetic on the parameter product prior to allocation.
Where hexwave functionality is not required, exclude STB_HEXWAVE_IMPLEMENTATION from build configurations to remove the vulnerable code path.

bash

# Configuration example
# See vendor advisory for patch details when available:
# https://github.com/nothings/stb/issues/1961