CVE-2018-8099: Incorrect returning of an error code in the index.c:read_entry() function leads to a double free in libgit2 be

Q: How do I fix CVE-2018-8099?

libgit2: upgrade to 0.26.2; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2018-8099 being exploited?

CVE-2018-8099 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2018-8099 affect?

CVE-2018-8099 affects libgit2, debian linux. Severity is medium (CVSS 6.5). Incorrect returning of an error code in the index.c:read_entry() function leads to a double free in libgit2 before v0.26.2, which allows an attacker to cause a denial of service via a crafted repository index file.

Q: How urgent is CVE-2018-8099?

Priority 46/100. On your watchlist

This month

MEDIUM 6.5WATCHLISTUPGRADEMITIGATE

CVE-2018-8099 is a medium-severity flaw (CVSS 6.5) affecting libgit2, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Incorrect returning of an error code in the index.c:read_entry() function leads to a double free in libgit2 before v0.26.2, which allows an attacker to cause a denial of service via a crafted repository index file.

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.4% (top 28%)
CISA exploited list	No
Weakness	CWE-415
Published	2018-03-14
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · libgit2

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-03-14 00:29 UTCPublished CVE record published
2026-06-17 02:04 UTCUpdated Record last modified

libgit2 libgit2 UPGRADE

Affected: < 0.26.2

Fixed in: 0.26.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy libgit2 || rpm -q libgit2 || libgit2 --version

2. UPGRADE to 0.26.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libgit2

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libgit2

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2018-8099?

libgit2: upgrade to 0.26.2; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-8099 being exploited?

CVE-2018-8099 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2018-8099 affect?

CVE-2018-8099 affects libgit2, debian linux. Severity is medium (CVSS 6.5). Incorrect returning of an error code in the index.c:read_entry() function leads to a double free in libgit2 before v0.26.2, which allows an attacker to cause a denial of service via a crafted repository index file.

How urgent is CVE-2018-8099?

Priority 46/100. On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2024-24577 HIGH 8.6 UPGRADE libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API
CVE-2024-24575 HIGH 7.5 UPGRADE libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API
CVE-2023-22742 MEDIUM 5.3 UPGRADE libgit2 is a cross-platform, linkable library implementation of Git
CVE-2020-12279 CRITICAL 9.8 UPGRADE MITIGATE An issue was discovered in libgit2 before 0.28.4 and 0.9x before 0.99.0
CVE-2020-12278 CRITICAL 9.8 UPGRADE MITIGATE An issue was discovered in libgit2 before 0.28.4 and 0.9x before 0.99.0

References

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