CVE-2021-20233
Last modified
CVE-2021-20233 is a high-severity vulnerability rated 8.2/10 on the CVSS scale. A flaw was found in grub2 in versions prior to 2.06. Setparam_prefix() in the menu rendering code performs a length calculation on the assumption that expressing a quoted single quote will require 3 characters, while it actually requires 4 characters which allows an attacker to corrupt memory by one byte for each quote in the input. EPSS estimates a 0.61% chance of exploitation in the next 30 days.
Description
A flaw was found in grub2 in versions prior to 2.06. Setparam_prefix() in the menu rendering code performs a length calculation on the assumption that expressing a quoted single quote will require 3 characters, while it actually requires 4 characters which allows an attacker to corrupt memory by one byte for each quote in the input. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Metrics
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Gnu | Grub2 | < 2.06 |
| Redhat | Enterprise Linux | 7.0 |
| Redhat | Enterprise Linux | 8.0 |
| Redhat | Enterprise Linux Server Aus | 7.2 |
| Redhat | Enterprise Linux Server Aus | 7.3 |
| Redhat | Enterprise Linux Server Aus | 7.4 |
| Redhat | Enterprise Linux Server Aus | 7.6 |
| Redhat | Enterprise Linux Server Aus | 7.7 |
| Redhat | Enterprise Linux Server Aus | 8.2 |
| Redhat | Enterprise Linux Server Eus | 7.6 |
| Redhat | Enterprise Linux Server Eus | 7.7 |
| Redhat | Enterprise Linux Server Eus | 8.1 |
| Redhat | Enterprise Linux Server Tus | 7.4 |
| Redhat | Enterprise Linux Server Tus | 7.6 |
| Redhat | Enterprise Linux Server Tus | 7.7 |
| Redhat | Enterprise Linux Server Tus | 8.2 |
| Redhat | Enterprise Linux Workstation | 7.0 |
| Fedoraproject | Fedora | 33 |
| Fedoraproject | Fedora | 34 |
| Netapp | Ontap Select Deploy Administration Utility | All versions |
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1926263Issue Tracking, Patch, Third Party Advisory
- https://security.gentoo.org/glsa/202104-05Third Party Advisory
- https://security.netapp.com/advisory/ntap-20220325-0001/Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1926263Issue Tracking, Patch, Third Party Advisory
- https://security.gentoo.org/glsa/202104-05Third Party Advisory
- https://security.netapp.com/advisory/ntap-20220325-0001/Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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