A flaw was found in grub2 in versions prior to 2.06. Variable names present are expanded in the supplied command line into their corresponding variable contents, using a 1kB stack buffer for temporary storage, without sufficient bounds checking. If the function is called with a command line that references a variable with a sufficiently large payload, it is possible to overflow the stack buffer, corrupt the stack frame and control execution which could also circumvent Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
CVE-2020-27749
Score 6.7 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 6.7; sources differ by 0.0.
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 6.7
- EG Score
- 6.7(medium)
- EG Risk
- 35(Track)EG Risk 35/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity67% × 45%Exploitation1% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 43.8%
- KEV
- Not listed
Published
March 3, 2021
Last Modified
November 21, 2024
References (8)
- secalert@redhathttps://bugzilla.redhat.com/show_bug.cgi?id=1899966
- secalert@redhathttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZWZ36QK4IKU6MWDWNOOWKPH3WXZBHT2R/
- secalert@redhathttps://security.gentoo.org/glsa/202104-05
- secalert@redhathttps://security.netapp.com/advisory/ntap-20220325-0001/
- af854a3a-2127-422b-91ae-364da2661108https://bugzilla.redhat.com/show_bug.cgi?id=1899966
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZWZ36QK4IKU6MWDWNOOWKPH3WXZBHT2R/
- af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202104-05
- af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20220325-0001/
Vendor Advisories for CVE-2020-27749(13)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2021:3675Red Hat Product SecurityMedium
Red Hat Security Advisory: shim and fwupd security update
- RHSA-2021:2790Red Hat Product SecurityMedium
Red Hat Security Advisory: shim and fwupd security update
- RHSA-2021:2566Red Hat Product SecurityMedium
Red Hat Security Advisory: fwupd security update
- RHSA-2021:1734Red Hat Product SecurityMedium
Red Hat Security Advisory: shim security update
- RHSA-2021:0701Red Hat Product SecurityMedium
Red Hat Security Advisory: grub2 security update
- RHSA-2021:0700Red Hat Product SecurityMedium
Red Hat Security Advisory: grub2 security update
- RHSA-2021:0699Red Hat Product SecurityMedium
Red Hat Security Advisory: grub2 security update
- RHSA-2021:0702Red Hat Product SecurityMedium
Red Hat Security Advisory: grub2 security update
- +5 more
Patch Availability(12)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | grub-efi-arm64-signed (1.167.2+2.04-1ubuntu44.2) @ groovy | 2026-05-26 | ubuntu |
| redhat | shim-unsigned-x64-0:15.4-4.el8_1 | 2021-09-28 | redhat |
| redhat | fwupd-0:1.5.9-1.el8_4 | 2021-06-29 | redhat |
| redhat | grub2-1:2.02-0.86.el7_4.2 | 2021-03-02 | redhat |
| redhat | grub2-1:2.02-0.86.el7_6.3 | 2021-03-02 | redhat |
| redhat | grub2-1:2.02-90.el8_3.1 | 2021-03-02 | redhat |
| redhat | grub2-1:2.02-0.87.el7_9.2 | 2021-03-02 | redhat |
| redhat | grub2-1:2.02-87.el8_1.2 | 2021-03-02 | redhat |
| redhat | grub2-1:2.02-0.86.el7_7.3 | 2021-03-02 | redhat |
| redhat | grub2-1:2.02-0.86.el7_2.2 | 2021-03-02 | redhat |
| redhat | grub2-1:2.02-87.el8_2.3 | 2021-03-02 | redhat |
| redhat | grub2-1:2.02-0.86.el7_3.2 | 2021-03-02 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(2)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
- Microsoft MSRCCVE-2020-277492021-03-11
A flaw was found in grub2 in versions prior to 2.06. Variable names present are expanded in the supplied command line into their corresponding variable contents using a 1kB stack buffer for temporary storage without sufficient bounds checking. If the function is called with a command line that references a variable with a sufficiently large payload it is possible to overflow the stack buffer corrupt the stack frame and control execution which could also circumvent Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
- UbuntuUSN-4992-1MEDIUM
GRUB 2 vulnerabilities
Data Freshness Timeline
(refreshed 13× in last 7d / 45× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-23 01:52 UTCEG score recompute
- 2026-07-22 22:38 UTCEG score recompute
- 2026-07-22 14:05 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-20 17:04 UTCEPSS rescore
- 2026-07-20 17:04 UTCEPSS rescore
- 2026-07-19 14:28 UTCEPSS rescore
- 2026-07-19 14:28 UTCEPSS rescore
- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-19 00:59 UTCOSV refresh
- 2026-07-16 16:59 UTCEPSS rescore
- 2026-07-15 16:55 UTCEPSS rescore
- 2026-07-15 16:55 UTCEPSS rescore
- 2026-07-15 01:57 UTCEPSS rescore
- 2026-07-13 22:27 UTCEPSS rescore
- 2026-07-13 22:27 UTCEPSS rescore
- 2026-07-13 06:10 UTCEPSS rescore
- 2026-07-13 06:10 UTCEPSS rescore
- 2026-07-12 05:44 UTCEPSS rescore
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-09 19:07 UTCEPSS rescore
- 2026-07-08 15:12 UTCEPSS rescore
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- 2026-07-07 13:43 UTCEPSS rescore
- 2026-07-06 16:25 UTCEPSS rescore
- 2026-07-06 16:25 UTCEPSS rescore
- 2026-07-06 02:21 UTCEPSS rescore
- 2026-07-06 02:21 UTCEPSS rescore
- 2026-07-04 06:29 UTCEPSS rescore
- 2026-07-04 06:29 UTCEPSS rescore
- 2026-07-01 07:48 UTCOSV refresh
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-29 14:04 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-27 03:06 UTCEPSS rescore
- 2026-06-27 03:06 UTCEPSS rescore
- 2026-06-25 13:48 UTCEPSS rescore
- 2026-06-24 14:03 UTCEPSS rescore
- 2026-06-24 14:03 UTCEPSS rescore
- 2026-06-23 21:31 UTCEPSS rescore
- 2026-06-23 21:31 UTCEPSS rescore
- 2026-06-22 14:23 UTCEPSS rescore
- 2026-06-22 14:23 UTCEPSS rescore
- 2026-06-21 14:54 UTCEPSS rescore
- 2026-06-21 14:54 UTCEPSS rescore
- 2026-06-21 01:57 UTCEPSS rescore
- 2026-06-19 19:24 UTCEPSS rescore
- 2026-06-19 19:23 UTCEPSS rescore
- 2026-06-18 17:50 UTCEPSS rescore
- 2026-06-18 17:50 UTCEPSS rescore
- 2026-06-17 17:50 UTCEPSS rescore
- 2026-06-16 17:50 UTCEPSS rescore
- 2026-06-15 17:46 UTCEPSS rescore
- 2026-06-14 23:15 UTCEPSS rescore
- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-13 12:43 UTCOSV refresh
- 2026-06-12 23:10 UTCEPSS rescore
- 2026-06-11 13:58 UTCEPSS rescore
- 2026-06-10 22:16 UTCEPSS rescore
- 2026-06-10 13:20 UTCEPSS rescore
- 2026-06-08 14:15 UTCEPSS rescore
- 2026-06-07 15:23 UTCEPSS rescore
- 2026-06-07 15:23 UTCEPSS rescore
- 2026-06-07 15:23 UTCEPSS rescore
- 2026-06-06 13:46 UTCEPSS rescore
- 2026-06-06 13:45 UTCEPSS rescore
- 2026-06-05 22:45 UTCEPSS rescore
- 2026-06-05 22:45 UTCEPSS rescore
- 2026-06-05 06:08 UTCEPSS rescore
- 2026-06-05 06:08 UTCEPSS rescore
- 2026-06-04 13:10 UTCEPSS rescore
- 2026-06-04 13:10 UTCEPSS rescore
- 2026-06-02 20:11 UTCEPSS rescore
- 2026-06-02 20:11 UTCEPSS rescore
- 2026-06-01 13:50 UTCEPSS rescore
- 2026-05-31 22:29 UTCEPSS rescore
- 2026-05-31 22:29 UTCEPSS rescore
- 2026-05-31 00:15 UTCEPSS rescore
- 2026-05-31 00:15 UTCEPSS rescore
- 2026-05-29 13:42 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-27 13:39 UTCEPSS rescore
- 2026-05-27 13:39 UTCEPSS rescore
- 2026-05-26 20:14 UTCEG score recompute
- 2026-05-26 20:14 UTCVendor advisory
- 2026-05-26 20:14 UTCGHSA enrichment
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-23 09:01 UTCOSV refresh
Frequently asked(5)
What is CVE-2020-27749?
When was CVE-2020-27749 disclosed?
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What is the CVSS score of CVE-2020-27749?
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Dependency Blast Radius
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