CVE-2015-8370

Exp

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.

Published: 2015-12-16 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2015-8370 is rated High Exploit Risk (75.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 4.70%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2015-8370

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2015-8370

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-09 5.05% 4.70% -0.35%
2 2026-04-01 3.05% 5.05% +2.00%
3 2026-02-26 — 3.05% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2015-8370

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.4 3.1 HIGH
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.4 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0
6.9 2.0 MEDIUM
AV:L/AC:M/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 3.4 10.0 [email protected]

Weakness enumeration for CVE-2015-8370

OS Trackers for CVE-2015-8370

vendor priority summary link
debian not yet assigned CVE-2015-8370 not yet assigned priority: Debian including 1 source packages (grub2), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2015-8370
gentoo normal CVE-2015-8370: 1 GLSA(s) (201512-03), 1 atom(s) (sys-boot/grub); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2015-8370
redhat medium — https://access.redhat.com/security/cve/CVE-2015-8370
suse medium CVE-2015-8370 severity moderate: SUSE including 448 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 532 product×package rows across 53 product lines (SUSE Liberty Linux 7, SUSE Linux Enterprise Desktop 11 SP3, … (53 product lines)): Fixed 375, Known Affected 157. https://www.suse.com/security/cve/CVE-2015-8370/
ubuntu medium CVE-2015-8370 medium priority: Ubuntu including 1 source packages (grub2), 5 status rows across 5 suites (precise, trusty, upstream, vivid, wily): released 4, needed 1. https://ubuntu.com/security/CVE-2015-8370

Affected software / configurations for CVE-2015-8370

Vendor Product Version Raw CPE
gnu grub2 1.98 cpe:2.3:a:gnu:grub2:1.98:*:*:*:*:*:*:*
gnu grub2 1.99 cpe:2.3:a:gnu:grub2:1.99:*:*:*:*:*:*:*
gnu grub2 2.00 cpe:2.3:a:gnu:grub2:2.00:*:*:*:*:*:*:*
gnu grub2 2.01 cpe:2.3:a:gnu:grub2:2.01:*:*:*:*:*:*:*
gnu grub2 2.02 cpe:2.3:a:gnu:grub2:2.02:*:*:*:*:*:*:*
fedoraproject fedora 23 cpe:2.3:o:fedoraproject:fedora:23:*:*:*:*:*:*:*

References for CVE-2015-8370

URL Tags
http://hmarco.org/bugs/CVE-2015-8370-Grub2-authentication-bypass.html Exploit
http://lists.fedoraproject.org/pipermail/package-announce/2015-December/173703.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-December/174049.html
http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00037.html
http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00039.html
http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00040.html
http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00041.html
http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00043.html
http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00044.html
http://lists.opensuse.org/opensuse-security-announce/2016-01/msg00003.html
http://packetstormsecurity.com/files/134831/Grub2-Authentication-Bypass.html
http://rhn.redhat.com/errata/RHSA-2015-2623.html
http://seclists.org/fulldisclosure/2015/Dec/69
http://www.debian.org/security/2015/dsa-3421
http://www.openwall.com/lists/oss-security/2015/12/15/6
http://www.openwall.com/lists/oss-security/2024/01/15/3
http://www.oracle.com/technetwork/topics/security/cpujan2016-2367955.html Patch
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
http://www.securityfocus.com/archive/1/537115/100/0/threaded
http://www.securityfocus.com/bid/79358
http://www.securitytracker.com/id/1034422
http://www.ubuntu.com/usn/USN-2836-1
https://security.gentoo.org/glsa/201512-03
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