TI-2015-06891 Aliases CVE-2015-8370 GHSA-jjvg-65v4-v3cq

Multiple integer underflows in Grub2 1.98 through 2.02 allow physically proximate…

HIGH 68CWE-191Published 2015-12-16 · Updated 2024-10-21

Key facts

Attack vector: Local
Privileges required: None
User interaction: None
Attack complexity: High
Impact type: Code execution, Security bypass
Confidentiality · integrity · availability: High · High · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-191, CWE-264 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.01095 65th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed Red Hat: 1 advisory

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
—	—	all versions	—	No fix listed	CNA

— Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 6

CPE	Versions	Role	Vendor
cpe:2.3:a:gnu:grub2:1.98:::::::*	1.98	Vulnerable	GNU
cpe:2.3:a:gnu:grub2:1.99:::::::*	1.99	Vulnerable	GNU
cpe:2.3:a:gnu:grub2:2.00:::::::*	2.00	Vulnerable	GNU
cpe:2.3:a:gnu:grub2:2.01:::::::*	2.01	Vulnerable	GNU
cpe:2.3:a:gnu:grub2:2.02:::::::*	2.02	Vulnerable	GNU
cpe:2.3:o:fedoraproject:fedora:23:::::::*	23	Vulnerable	Fedoraproject

cpe:2.3:a:gnu:grub2:1.98:*:*:*:*:*:*:* Versions 1.98 Vulnerable ·GNU
cpe:2.3:a:gnu:grub2:1.99:*:*:*:*:*:*:* Versions 1.99 Vulnerable ·GNU
cpe:2.3:a:gnu:grub2:2.00:*:*:*:*:*:*:* Versions 2.00 Vulnerable ·GNU
cpe:2.3:a:gnu:grub2:2.01:*:*:*:*:*:*:* Versions 2.01 Vulnerable ·GNU
cpe:2.3:a:gnu:grub2:2.02:*:*:*:*:*:*:* Versions 2.02 Vulnerable ·GNU
cpe:2.3:o:fedoraproject:fedora:23:*:*:*:*:*:*:* Versions 23 Vulnerable ·Fedoraproject

Remediation

Red Hat 1 advisory

RHSA-2015:2623 Released 2015-12-15 · Red Hat rating Moderate
grub2 security and bug fix update
- Red Hat Enterprise Linux Client (v. 7) grub2-1:2.02-0.33.el7_2, grub2-efi-1:2.02-0.33.el7_2, grub2-tools-1:2.02-0.33.el7_2
- Red Hat Enterprise Linux Client Optional (v. 7) grub2-efi-modules-1:2.02-0.33.el7_2
- Red Hat Enterprise Linux ComputeNode (v. 7) grub2-1:2.02-0.33.el7_2, grub2-efi-1:2.02-0.33.el7_2, grub2-tools-1:2.02-0.33.el7_2
- Red Hat Enterprise Linux ComputeNode Optional (v. 7) grub2-efi-modules-1:2.02-0.33.el7_2
- Red Hat Enterprise Linux Server (v. 7) grub2-1:2.02-0.33.el7_2, grub2-efi-1:2.02-0.33.el7_2, grub2-tools-1:2.02-0.33.el7_2
- Red Hat Enterprise Linux Server Optional (v. 7) grub2-efi-modules-1:2.02-0.33.el7_2
- Red Hat Enterprise Linux Workstation (v. 7) grub2-1:2.02-0.33.el7_2, grub2-efi-1:2.02-0.33.el7_2, grub2-tools-1:2.02-0.33.el7_2
- Red Hat Enterprise Linux Workstation Optional (v. 7) grub2-efi-modules-1:2.02-0.33.el7_2

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux Client (v. 7)	Fixed	RHSA-2015:2623
Red Hat Enterprise Linux Client Optional (v. 7)	Fixed	RHSA-2015:2623
Red Hat Enterprise Linux ComputeNode (v. 7)	Fixed	RHSA-2015:2623
Red Hat Enterprise Linux ComputeNode Optional (v. 7)	Fixed	RHSA-2015:2623
Red Hat Enterprise Linux Server (v. 7)	Fixed	RHSA-2015:2623
Red Hat Enterprise Linux Server Optional (v. 7)	Fixed	RHSA-2015:2623
Red Hat Enterprise Linux Workstation (v. 7)	Fixed	RHSA-2015:2623
Red Hat Enterprise Linux Workstation Optional (v. 7)	Fixed	RHSA-2015:2623

Not affected: 3 products

Red Hat Enterprise Linux 5
Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 8

Timeline

2026-10-02 Threatist record created from CVE-2015-8370
2026-10-03 Alias added: GHSA-jjvg-65v4-v3cq

References

Exploit 1

http://hmarco.org/bugs/CVE-2015-8370-Grub2-authentication-bypass.html

Patch 1

http://www.oracle.com/technetwork/topics/security/cpujan2016-2367955.html

Advisory 13

Other 5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences