8.1
HIGH CVSS 3.1
CVE-2021-41253
Possible heap buffer overflow when using zycore string functions in formatter hooks
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.

INFO

Published Date :

Nov. 8, 2021, 10:15 p.m.

Last Modified :

Nov. 21, 2024, 6:25 a.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2021-41253 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Zyantific zydis
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 MEDIUM [email protected]
CVSS 3.1 MEDIUM [email protected]
CVSS 3.1 HIGH [email protected]
Solution
This information is provided by the 3rd party feeds.
  • Update the affected packages.
References to Advisories, Solutions, and Tools
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-41253 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-41253 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-41253 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-41253 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://github.com/zyantific/zydis/commit/55dd08c210722aed81b38132f5fd4a04ec1943b5
    Added Reference https://github.com/zyantific/zydis/security/advisories/GHSA-q42v-hv86-3m4g
    Added Reference https://huntr.dev/bounties/96b0a482-7041-45b1-9327-c6a4a8f32d3a
    Added Reference https://huntr.dev/bounties/d2536d7d-36ce-4723-928c-98d1ee039784
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • Reanalysis by [email protected]

    Oct. 24, 2022

    Action Type Old Value New Value
    Added CWE NIST CWE-908
  • Initial Analysis by [email protected]

    Nov. 15, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:M/Au:N/C:P/I:P/A:P)
    Added CVSS V3.1 NIST AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
    Changed Reference Type https://github.com/zyantific/zydis/commit/55dd08c210722aed81b38132f5fd4a04ec1943b5 No Types Assigned https://github.com/zyantific/zydis/commit/55dd08c210722aed81b38132f5fd4a04ec1943b5 Patch, Third Party Advisory
    Changed Reference Type https://github.com/zyantific/zydis/security/advisories/GHSA-q42v-hv86-3m4g No Types Assigned https://github.com/zyantific/zydis/security/advisories/GHSA-q42v-hv86-3m4g Third Party Advisory
    Changed Reference Type https://huntr.dev/bounties/96b0a482-7041-45b1-9327-c6a4a8f32d3a No Types Assigned https://huntr.dev/bounties/96b0a482-7041-45b1-9327-c6a4a8f32d3a Exploit, Third Party Advisory
    Changed Reference Type https://huntr.dev/bounties/d2536d7d-36ce-4723-928c-98d1ee039784 No Types Assigned https://huntr.dev/bounties/d2536d7d-36ce-4723-928c-98d1ee039784 Exploit, Patch, Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:a:zyantific:zydis:*:*:*:*:*:*:*:* versions up to (including) 3.2.0
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 8.1
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 6.8
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.55 }} 0.03%

score

0.66818

percentile