CVE-2018-10887 [High] | Out-of-bounds Read in Libgit2

A flaw was found in libgit2 before version 0.27.3. It has been discovered that an unexpected sign extension in git_delta_apply function in delta.c file may lead to an integer overflow which in turn leads to an out of bound read, allowing to read before the base object. An attacker may use this flaw to leak memory addresses or cause a Denial of Service.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.35%	2.05%	+1.70%
2	2026-05-08	0.26%	0.35%	+0.09%
3	2026-03-11	—	0.26%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.35%

2.05%

+1.70%

2026-05-08

0.26%

0.35%

+0.09%

2026-03-11

—

0.26%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.1	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/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:H) Serious risk that confidential data gets exposed in a big 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	5.2	[email protected]
5.8	2.0	MEDIUM	`AV:N/AC:M/Au:N/C:P/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:P) Partial confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	8.6	4.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.1

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/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:H): Serious risk that confidential data gets exposed in a big 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

5.2

[email protected]

5.8

2.0

MEDIUM

AV:N/AC:M/Au:N/C:P/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:P): Partial confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

8.6

4.9

[email protected]

Weakness enumeration for CVE-2018-10887

OS Trackers for CVE-2018-10887

vendor	priority	summary	link
`alpine`	—	CVE-2018-10887: 4 source package rows (libgit2, libgit2-1.0, libgit2-1.1, libgit2-1.5); 16 state rows across 9 repos (3.10-main, 3.11-main, 3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 12, open 4.	https://security.alpinelinux.org/vuln/CVE-2018-10887
`debian`	low	CVE-2018-10887 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-2018-10887
`suse`	medium	CVE-2018-10887 severity moderate: SUSE including 29 source package names (libgit2, libgit2-1_1-1.1.1-1.2, …), 52 product×package rows across 26 product lines (SUSE Linux Enterprise Module for Development Tools 15, SUSE Linux Enterprise Module for Development Tools 15 SP1, … (26 product lines)): Fixed 46, Known Not Affected 6.	https://www.suse.com/security/cve/CVE-2018-10887/
`ubuntu`	medium	CVE-2018-10887 medium priority: Ubuntu including 1 source packages (libgit2), 5 status rows across 5 suites (artful, bionic, trusty, upstream, xenial): released 4, ignored 1.	https://ubuntu.com/security/CVE-2018-10887

Affected software / configurations for CVE-2018-10887

Vendor	Product	Version	Raw CPE
libgit2	libgit2	< 0.27.3	cpe:2.3:a:libgit2:libgit2::::::::
debian	debian_linux	8.0	cpe:2.3:o:debian:debian_linux:8.0:::::::*
debian	debian_linux	9.0	cpe:2.3:o:debian:debian_linux:9.0:::::::*

References for CVE-2018-10887

URL	Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1598021	Issue Tracking Patch
https://github.com/libgit2/libgit2/commit/3f461902dc1072acb8b7607ee65d0a0458ffac2a	Patch
https://github.com/libgit2/libgit2/commit/c1577110467b701dcbcf9439ac225ea851b47d22	Patch
https://github.com/libgit2/libgit2/releases/tag/v0.27.3	Patch Release Notes
https://lists.debian.org/debian-lts-announce/2018/08/msg00024.html	Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/03/msg00031.html	Mailing List Third Party Advisory

URL

CVE-2018-10887

Exploit prediction scoring system (EPSS) score for CVE-2018-10887

Common vulnerability scoring system (CVSS) metrics for CVE-2018-10887

Weakness enumeration for CVE-2018-10887

OS Trackers for CVE-2018-10887

Affected software / configurations for CVE-2018-10887

References for CVE-2018-10887