What’s Vulnerable › Vulnerabilities
CVE-2024-25629: c-ares out of bounds read in ares__read_line()
- Severity: medium (CVSS 5.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2024-02-23 · updated 2026-06-17
- Weakness: CWE-127
Description
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 which may result in a crash. This issue is fixed in c-ares 1.27.0. No known workarounds exist.
Affected products
- c-ares: before 1.27.0 — fixed in 1.27.0
- Fedoraproject Fedora: 38, 39, 40
How to fix
Upgrade to a fixed version: c-ares 1.27.0. Check the vendor advisory for mitigations.
References
- https://github.com/c-ares/c-ares/commit/a804c04ddc8245fc8adf0e92368709639125e183
- https://github.com/c-ares/c-ares/security/advisories/GHSA-mg26-v6qh-x48q
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2P76QYINQNPEHUTEEDOUYIRZ2X6UVZ5K/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/CSCMTSPDIE2UHU34TIXQQHZ6JTE3Y3VF/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GX37LFPFQ3T6FFMMFYQTEGIQXXN7F27U/
- https://github.com/c-ares/c-ares/commit/a804c04ddc8245fc8adf0e92368709639125e183
- https://github.com/c-ares/c-ares/security/advisories/GHSA-mg26-v6qh-x48q
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2P76QYINQNPEHUTEEDOUYIRZ2X6UVZ5K/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/CSCMTSPDIE2UHU34TIXQQHZ6JTE3Y3VF/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GX37LFPFQ3T6FFMMFYQTEGIQXXN7F27U/
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