CVE-2026-102521
Received Received - Intake

Decoder Memory Exposure in lib0

Publication date: 2026-09-29

Last updated on: 2026-09-29

Assigner: GitHub, Inc.

Description
The decoder in `readFromDataView` in lib0 before 0.2.119 can be tricked into reading more than it should from a buffer. The vulnerability allows reading past the decoders' view, thus exposing adjacent process memory. This can be anything that is currently in the head, for example credentials or logs. This is similar to but different from GHSA-r5c8-rf4w-qrq8.

CVSS Scores

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Meta Information

Published
2026-09-29
Last Modified
2026-09-29
Generated
2026-09-29
AI Q&A
2026-09-29
EPSS Evaluated
N/A
NVD
CVE-2026-102521
EUVD
EUVD-2026-88820

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
lib0 lib0 to 0.2.119 (exc)
dmonad lib0 to 0.2.119 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-125 The product reads data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

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Executive Summary

This vulnerability is an out-of-bounds read in the lib0 library's decoder function readFromDataView. It allows an attacker to trick the decoder into reading beyond the intended buffer, exposing adjacent process memory such as credentials or logs. The issue occurs because the decoder does not properly check buffer boundaries during data processing.

Detection Guidance

This vulnerability involves an out-of-bounds read in the lib0 library's decoder functions. To detect it, inspect your system for applications using lib0 versions prior to 0.2.119. Check for memory exposure risks in decoders processing untrusted input. No direct network detection commands are provided, but monitor for unusual memory leaks or exposed credentials.

Impact Analysis

This vulnerability can expose sensitive data like credentials or logs stored in adjacent memory. Attackers could exploit it to leak confidential information from the process memory, potentially leading to unauthorized access or data breaches. The impact is high due to the CVSS score of 8.6 and the fact that no user interaction or privileges are required.

Compliance Impact

This vulnerability could lead to unauthorized exposure of personal or sensitive data, violating compliance requirements under GDPR and HIPAA. GDPR mandates protection of personal data, while HIPAA requires safeguarding protected health information. A breach could result in legal penalties, fines, or reputational damage due to non-compliance.

Mitigation Strategies

Update the lib0 library to version 0.2.119 or later to address the out-of-bounds read vulnerability in the decoder functions.

  • Review and replace any direct usage of `readFromDataView` or `readUint8Array` functions with the updated safe alternatives provided in the patch.
  • Audit your codebase for instances where `Uint8Array` views are created directly on shared buffers, and replace them with the new `subarray` or `subdataview` helper functions.

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