Process memory disclosure via unterminated user_name variant
Published Nov 24, 2021 · Updated Sep 16, 2024
An out-of-bounds read in affected Zoom products allows remote attackers to disclose process memory through crafted meeting traffic. The MMR converts an unterminated user_name byte-array variant into a string, copies adjacent uninitialized memory until a null byte, and returns it as a browser-visible display name. Meeting participation reaches the path without victim interaction; pointer disclosure was demonstrated on MMR servers, while useful client-side exfiltration was not established.
Summary
What happened
An out-of-bounds read in affected Zoom products allows remote attackers to disclose process memory through crafted meeting traffic. The MMR converts an unterminated user_name byte-array variant into a string, copies adjacent uninitialized memory until a null byte, and returns it as a browser-visible display name. Meeting participation reaches the path without victim interaction; pointer disclosure was demonstrated on MMR servers, while useful client-side exfiltration was not established.
The record
- CVE
- CVE-2021-34424
- Published
- Nov 24, 2021
- Updated
- Sep 16, 2024
- Vendor
- Zoom Video Communications, Inc.
- Product
- Zoom Meeting SDK for macOS
- Classifications
- CWE-125
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Nov 24, 2021CVE publishedPublication date reported by the CVE source.
- Sep 16, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <5.7.6.1340
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Project Zero MMR user_name variant proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo