PatchTheCVECVE-2021-41253: Zydis is an x86/x86-64 disassembler library
CVE-2021-41253 is a medium-severity flaw (CVSS 5.9) affecting zydis. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 co
Why this priority
- Public exploit reference
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-41253?
zydis: upgrade to newer than 3.2.0. Exact commands for each OS are on this page.
Is CVE-2021-41253 being exploited?
CVE-2021-41253 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-41253 affect?
CVE-2021-41253 affects zydis. Severity is medium (CVSS 5.9). 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
How urgent is CVE-2021-41253?
Priority 50/100. Public exploit reference; Remotely exploitable, no login, no user action