CVE-2024-25629: c-ares is a C library for asynchronous DNS requests

Q: How do I fix CVE-2024-25629?

c-ares: upgrade to 1.27.0; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2024-25629 being exploited?

CVE-2024-25629 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-2024-25629 affect?

CVE-2024-25629 affects c-ares, fedora. Severity is medium (CVSS 4.4). c-ares is a C library for asynchronous DNS requests. `ares__read_line()` is used to parse local configuration files such as `/etc/resolv.conf`, `/etc/nsswitch.conf`, the `HOSTALIASES` file, and if using a c-ares version prior to 1.27.0, the

Q: How urgent is CVE-2024-25629?

Priority 23/100. No elevated risk signals yet.

Routine

MEDIUM 4.4UPGRADEMITIGATE

CVE-2024-25629 is a medium-severity flaw (CVSS 4.4) affecting c-ares, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

c-ares is a C library for asynchronous DNS requests. `ares__read_line()` is used to parse local configuration files such as `/etc/resolv.conf`, `/etc/nsswitch.conf`, the `HOSTALIASES` file, and if using a c-ares version prior to 1.27.0, the `/etc/hosts` file. If any of these configuration files has an embedded `NULL` character as the first character in a new line, it can lead to attempting to read memory prior to the start of the given buffer whi

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.4 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	0.4% (top 71%)
CISA exploited list	No
Weakness	CWE-127, CWE-125
Published	2024-02-23
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: c-ares · fedoraproject

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

Am I affected?

Timeline

2024-02-23 15:15 UTCPublished CVE record published
2026-06-17 07:16 UTCUpdated Record last modified

c-ares c-ares UPGRADE

Affected: < 1.27.0

Fixed in: 1.27.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy c-ares || rpm -q c-ares || c-ares --version

2. UPGRADE to 1.27.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade c-ares

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade c-ares

Note

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

fedoraproject fedora MITIGATE

Affected: 38 · 39 · 40

Fixed in: no fixed release known

Safe to downgrade to: a release before 38

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-2024-25629?

c-ares: upgrade to 1.27.0; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2024-25629 being exploited?

CVE-2024-25629 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-2024-25629 affect?

CVE-2024-25629 affects c-ares, fedora. Severity is medium (CVSS 4.4). c-ares is a C library for asynchronous DNS requests. `ares__read_line()` is used to parse local configuration files such as `/etc/resolv.conf`, `/etc/nsswitch.conf`, the `HOSTALIASES` file, and if using a c-ares version prior to 1.27.0, the

How urgent is CVE-2024-25629?

Priority 23/100. No elevated risk signals yet.

Related CVEs

CVE-2025-62408 MEDIUM 5.9 UPGRADE c-ares is an asynchronous resolver library
CVE-2023-32067 HIGH 7.5 UPGRADE MITIGATE c-ares is an asynchronous resolver library
CVE-2023-31147 MEDIUM 5.9 UPGRADE MITIGATE c-ares is an asynchronous resolver library
CVE-2023-31130 MEDIUM 4.1 UPGRADE MITIGATE c-ares is an asynchronous resolver library
CVE-2023-31124 LOW 3.7 UPGRADE MITIGATE c-ares is an asynchronous resolver library

References

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