CVE-2021-20225
A flaw was found in grub2 in versions prior to 2.06. The option parser allows an attacker to write past the end of a heap-allocated buffer by calling certain commands with a large number of specific
02 Description
A flaw was found in grub2 in versions prior to 2.06. The option parser allows an attacker to write past the end of a heap-allocated buffer by calling certain commands with a large number of specific
03 Exploitation and scoring
- Exploitation
- Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
- SSVC decision
- Not assessed by CISA
- EPSS probability
- 1.00% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 62.7% of scored records. A rank, not a probability.
- NVD base score
- 6.7 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-06-17.
- Red Hat severity
- Moderate. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2021-03-03 16:44Z5 YR AGO
- Last updated
- 2024-08-03 17:30Z2 YR AGO
- Reserved
- 2020-12-17
- Assigning CNA
- redhat
- Record state
- PUBLISHED
- Severity
- Not rated by the issuing CNA
- CNA CVSS vector
- Not published by the issuing CNA
- Weaknesses
- CWE-787Out-of-bounds WriteBase
- Data version
- 5.1
- Document digest
- 05f0b3bf9b2c823670c2bf680f4f313bdaec9ea92b7765ac8ab4a659057cfc80
05 Affected products
06 References
- bugzilla.redhat.comhttps://bugzilla.redhat.com/show_bug.cgi?id=1924696
- lists.fedoraproject.orgFEDORA-2021-cab258a413https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZWZ36QK4IKU6MWDWNOOWKPH3WXZBHT2R/
- security.gentoo.orgGLSA-202104-05https://security.gentoo.org/glsa/202104-05
- security.netapp.comhttps://security.netapp.com/advisory/ntap-20220325-0001/
07 Fixed in
AlmaLinux 8
- shim-aa64 Fixed in 15.4-2.el8_1.alma
- shim-ia32 Fixed in 15.4-2.el8_1.alma
- shim-unsigned-aarch64 Fixed in 15-7.el8_1.alma
- shim-unsigned-x64 Fixed in 15.4-4.el8_1.alma
- shim-x64 Fixed in 15.4-2.el8_1.alma
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Arch Linux
- grub Fixed in 2:2.06-1
Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.
CloudLinux 8
- shim-aa64 Fixed in 15.4-2.el8_1.alma
- shim-ia32 Fixed in 15.4-2.el8_1.alma
- shim-unsigned-aarch64 Fixed in 15-7.el8_1.alma
- shim-unsigned-x64 Fixed in 15.4-4.el8_1.alma
- shim-x64 Fixed in 15.4-2.el8_1.alma
Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- grub2 Fixed in 2.04-16
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- grub2 Fixed in 2.04-16
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- grub2 Fixed in 2.04-16
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 18.04 LTS
- grub2-signed Fixed in 1.167~18.04.5
- grub2-unsigned Fixed in 2.04-1ubuntu44.1.2
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 20.04 LTS
- grub2-signed Fixed in 1.167.2
- grub2-unsigned Fixed in 2.04-1ubuntu44.2
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 14.04 LTS
- grub2-signed No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.