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CVE-2021-41253 Detail

Description

Zydis is an x86/x86-64 disassembler library. Users of Zydis versions v3.2.0 and older that use the string functions provided in `zycore` in order to append untrusted user data to the formatter buffer within their custom formatter hooks can run into heap buffer overflows. Older versions of Zydis failed to properly initialize the string object within the formatter buffer, forgetting to initialize a few fields, leaving their value to chance. This could then in turn cause zycore functions like `ZyanStringAppend` to make incorrect calculations for the new target size, resulting in heap memory corruption. This does not affect the regular uncustomized Zydis formatter, because Zydis internally doesn't use the string functions in zycore that act upon these fields. However, because the zycore string functions are the intended way to work with the formatter buffer for users of the library that wish to extend the formatter, we still consider this to be a vulnerability in Zydis. This bug is patched starting in version 3.2.1. As a workaround, users may refrain from using zycore string functions in their formatter hooks until updating to a patched version.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/zyantific/zydis/commit/55dd08c210722aed81b38132f5fd4a04ec1943b5 Patch  Third Party Advisory 
https://github.com/zyantific/zydis/security/advisories/GHSA-q42v-hv86-3m4g Third Party Advisory 
https://huntr.dev/bounties/96b0a482-7041-45b1-9327-c6a4a8f32d3a Exploit  Third Party Advisory 
https://huntr.dev/bounties/d2536d7d-36ce-4723-928c-98d1ee039784 Exploit  Patch  Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-908 Use of Uninitialized Resource cwe source acceptance level NIST  
CWE-122 Heap-based Buffer Overflow GitHub, Inc.  
CWE-457 Use of Uninitialized Variable GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-41253
NVD Published Date:
11/08/2021
NVD Last Modified:
10/24/2022
Source:
GitHub, Inc.