CVE-2018-8098 [Medium] | Integer Overflow in Libgit2

Integer overflow in the index.c:read_entry() function while decompressing a compressed prefix length in libgit2 before v0.26.2 allows an attacker to cause a denial of service (out-of-bounds read) via a crafted repository index file.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.74%	1.42%	+0.68%
2	2025-11-21	0.50%	0.74%	+0.24%
3	2025-11-18	—	0.50%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.74%

1.42%

+0.68%

2025-11-21

0.50%

0.74%

+0.24%

2025-11-18

—

0.50%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
6.5	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	3.6	[email protected]
4.3	2.0	MEDIUM	`AV:N/AC:M/Au:N/C:N/I:N/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:M) Exploitation needs some favorable conditions, but not exceptional ones. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	8.6	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

6.5

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

3.6

[email protected]

4.3

2.0

MEDIUM

AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:M): Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

8.6

2.9

[email protected]

OS Trackers for CVE-2018-8098

vendor	priority	summary	link
`alpine`	medium	CVE-2018-8098: 1 source package rows (libgit2); 4 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 4.	https://security.alpinelinux.org/vuln/CVE-2018-8098
`debian`	low	CVE-2018-8098 low priority: Debian including 1 source packages (libgit2), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2018-8098
`redhat`	low	—	https://access.redhat.com/security/cve/CVE-2018-8098
`suse`	medium	CVE-2018-8098 severity moderate: SUSE including 28 source package names (libgit2, libgit2-1_1-1.1.1-1.2, …), 66 product×package rows across 30 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (30 product lines)): Known Not Affected 39, Fixed 27.	https://www.suse.com/security/cve/CVE-2018-8098/
`ubuntu`	low	CVE-2018-8098 low priority: Ubuntu including 1 source packages (libgit2), 20 status rows across 20 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 15, needed 3, ignored 1, released 1.	https://ubuntu.com/security/CVE-2018-8098

Affected software / configurations for CVE-2018-8098

Vendor	Product	Version	Raw CPE
libgit2	libgit2	< 0.26.2	cpe:2.3:a:libgit2:libgit2::::::::
debian	debian_linux	9.0	cpe:2.3:o:debian:debian_linux:9.0:::::::*

References for CVE-2018-8098

URL	Tags
https://github.com/libgit2/libgit2/commit/3207ddb0103543da8ad2139ec6539f590f9900c1	Patch Third Party Advisory
https://github.com/libgit2/libgit2/commit/3db1af1f370295ad5355b8f64b865a2a357bcac0	Patch Third Party Advisory
https://libgit2.github.com/security/	Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/03/msg00031.html	Mailing List Third Party Advisory

URL

CVE-2018-8098

Exploit prediction scoring system (EPSS) score for CVE-2018-8098

Common vulnerability scoring system (CVSS) metrics for CVE-2018-8098

Weakness enumeration for CVE-2018-8098

OS Trackers for CVE-2018-8098

Affected software / configurations for CVE-2018-8098

References for CVE-2018-8098