Multiple integer underflows in Grub2 1.98 through 2.02 allow physically proximate attackers to bypass authentication, obtain sensitive information, or cause a denial of service (disk corruption) via backspace characters in the (1) grub_username_get function in grub-core/normal/auth.c or the (2) grub_password_get function in lib/crypto.c, which trigger an "Off-by-two" or "Out of bounds overwrite" memory error.
CVE-2015-8370
Score 7.4 from GitHub Security Advisory published 2022-05-14. NVD baseline CVSS 7.4; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.4
- EG Score
- 7.4(medium)
- EG Risk
- 49(Track*)EG Risk 49/100SSVC: 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 computedSeverity74% × 45%Exploitation40% × 40%Automatability0% × 15%Action: Watch closely — could escalate to Attend. - EPSS PROB
- 1%
- EPSS %ILE
- 63%
- KEV
- Not listed
Published
December 16, 2015
Last Modified
May 6, 2026
References (46)
- cve@mitrehttp://hmarco.org/bugs/CVE-2015-8370-Grub2-authentication-bypass.html
- cve@mitrehttp://lists.fedoraproject.org/pipermail/package-announce/2015-December/173703.html
- cve@mitrehttp://lists.fedoraproject.org/pipermail/package-announce/2015-December/174049.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-12/msg00037.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-12/msg00039.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-12/msg00040.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-12/msg00041.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-12/msg00043.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-12/msg00044.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2016-01/msg00003.html
- cve@mitrehttp://packetstormsecurity.com/files/134831/Grub2-Authentication-Bypass.html
- cve@mitrehttp://rhn.redhat.com/errata/RHSA-2015-2623.html
- cve@mitrehttp://seclists.org/fulldisclosure/2015/Dec/69
- cve@mitrehttp://www.debian.org/security/2015/dsa-3421
- cve@mitrehttp://www.openwall.com/lists/oss-security/2015/12/15/6
Patch Availability(2)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | grub2-common (2.02~beta2-29ubuntu0.2) @ wily | 2026-05-22 | ubuntu |
| redhat | grub2-1:2.02-0.33.el7_2 | 2015-12-15 | 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.
Affected Packages
(7 across 7 ecosystems)
Debian:11(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| grub2 | — | 2.02~beta2-33 | — |
Debian:12(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| grub2 | — | 2.02~beta2-33 | — |
Debian:13(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| grub2 | — | 2.02~beta2-33 | — |
Debian:14(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| grub2 | — | 2.02~beta2-33 | — |
Debian:6.0(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| grub2 | 1.98+20100804-14, 1.98+20100804-14+squeeze1 | 1.98+20100804-14+squeeze2 | — |
Debian:7(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| grub2 | 1.99-27+deb7u1, 1.99-27+deb7u2 | 1.99-27+deb7u3 | — |
Debian:8(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| grub2 | 2.02~beta2-22 | 2.02~beta2-22+deb8u1 | — |
All Vendor Advisories
(3)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
- Microsoft MSRCCVE-2015-83702020-08-18
Multiple integer underflows in Grub2 1.98 through 2.02 allow physically proximate attackers to bypass authentication obtain sensitive information or cause a denial of service (disk corruption) via backspace characters in the (1) grub_username_get function in grub-core/normal/auth.c or the (2) grub_password_get function in lib/crypto.c which trigger an "Off-by-two" or "Out of bounds overwrite" memory error.
- Red HatRHSA-2015:2623MODERATE2015-12-10
RHSA-2015:2623 — Moderate
- UbuntuUSN-2836-1MEDIUM
GRUB vulnerability
Data Freshness Timeline
(refreshed 7× in last 7d / 27× 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.
Showing the most recent 100 of 128 total refreshes for this CVE.
- 2026-08-21 23:44 UTCEPSS rescore
- 2026-08-20 22:50 UTCEPSS rescore
- 2026-08-19 16:59 UTCEPSS rescore
- 2026-08-18 13:43 UTCEPSS rescore
- 2026-08-16 14:51 UTCEPSS rescore
- 2026-08-16 02:09 UTCEPSS rescore
- 2026-08-15 01:25 UTCEPSS rescore
- 2026-08-14 14:54 UTCOSV refresh
- 2026-08-12 13:46 UTCEPSS rescore
- 2026-08-11 13:36 UTCEPSS rescore
- 2026-08-09 13:42 UTCEPSS rescore
- 2026-08-08 16:32 UTCEPSS rescore
- 2026-08-07 16:22 UTCEPSS rescore
- 2026-08-06 13:42 UTCEPSS rescore
- 2026-08-05 19:12 UTCEPSS rescore
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- 2026-08-04 10:31 UTCEPSS rescore
- 2026-08-01 04:11 UTCEPSS rescore
- 2026-07-30 03:24 UTCOSV refresh
- 2026-07-30 01:26 UTCEPSS rescore
- 2026-07-30 01:26 UTCEPSS rescore
- 2026-07-28 15:31 UTCEPSS rescore
- 2026-07-26 14:50 UTCEPSS rescore
- 2026-07-25 14:13 UTCEPSS rescore
- 2026-07-24 14:13 UTCEPSS rescore
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- 2026-07-23 14:14 UTCEPSS rescore
- 2026-07-23 01:20 UTCEG score recompute
- 2026-07-23 00:21 UTCEG score recompute
- 2026-07-22 21:59 UTCEG score recompute
- 2026-07-22 14:04 UTCEPSS rescore
- 2026-07-21 15:21 UTCEPSS rescore
- 2026-07-21 15:21 UTCEPSS rescore
- 2026-07-20 17:03 UTCEPSS rescore
- 2026-07-19 14:27 UTCEPSS rescore
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- 2026-07-19 02:26 UTCEPSS rescore
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- 2026-07-18 10:00 UTCEPSS rescore
- 2026-07-16 16:59 UTCEPSS rescore
- 2026-07-15 16:54 UTCEPSS rescore
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- 2026-07-15 01:56 UTCEPSS rescore
- 2026-07-13 22:26 UTCEPSS rescore
- 2026-07-13 22:26 UTCEPSS rescore
- 2026-07-12 12:38 UTCOSV refresh
- 2026-07-12 05:42 UTCEPSS rescore
- 2026-07-11 08:23 UTCEPSS rescore
- 2026-07-09 19:05 UTCEPSS rescore
- 2026-07-09 19:05 UTCEPSS rescore
- 2026-07-08 15:10 UTCEPSS rescore
- 2026-07-07 13:42 UTCEPSS rescore
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- 2026-07-06 16:24 UTCEPSS rescore
- 2026-07-06 02:20 UTCEPSS rescore
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- 2026-07-04 06:28 UTCEPSS rescore
- 2026-07-01 15:02 UTCEPSS rescore
- 2026-06-30 23:19 UTCEPSS rescore
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- 2026-06-29 14:03 UTCEPSS rescore
- 2026-06-29 14:03 UTCEPSS rescore
- 2026-06-28 14:04 UTCEPSS rescore
- 2026-06-28 04:53 UTCEPSS rescore
- 2026-06-27 03:05 UTCEPSS rescore
- 2026-06-25 13:47 UTCEPSS rescore
- 2026-06-25 13:47 UTCEPSS rescore
- 2026-06-24 14:02 UTCEPSS rescore
- 2026-06-24 14:02 UTCEPSS rescore
- 2026-06-23 21:30 UTCEPSS rescore
- 2026-06-23 18:20 UTCOSV refresh
- 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
- 2026-06-21 01:57 UTCEPSS rescore
- 2026-06-19 19:23 UTCEPSS rescore
- 2026-06-19 19:23 UTCEPSS rescore
- 2026-06-18 17:50 UTCEPSS rescore
- 2026-06-17 17:50 UTCEPSS rescore
- 2026-06-17 17:49 UTCEPSS rescore
- 2026-06-16 17:50 UTCEPSS rescore
- 2026-06-16 17:50 UTCEPSS rescore
- 2026-06-15 17:45 UTCEPSS rescore
- 2026-06-14 23:14 UTCEPSS rescore
- 2026-06-13 22:57 UTCEPSS rescore
- 2026-06-12 23:09 UTCEPSS rescore
- 2026-06-12 23:09 UTCEPSS rescore
- 2026-06-11 13:57 UTCEPSS rescore
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- 2026-06-10 22:15 UTCEPSS rescore
- 2026-06-10 13:18 UTCEPSS rescore
- 2026-06-08 14:14 UTCEPSS rescore
- 2026-06-07 15:22 UTCEPSS rescore
- 2026-06-07 01:29 UTCOSV refresh
- 2026-06-06 13:45 UTCEPSS rescore
- 2026-06-05 22:44 UTCEPSS rescore
- 2026-06-05 06:08 UTCEPSS rescore
- 2026-06-05 06:08 UTCEPSS rescore
- 2026-06-04 13:10 UTCEPSS rescore
Frequently asked(5)
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