Denial of service in c-ares

1) Use-after-free

EUVDB-ID: #VU119383

Risk: Medium

CVSSv4.0: 2.3 [CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-62408

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service attack.

The vulnerability exists due to a use-after-free error within the read_answer() function when process_answer() terminates a query such as after maximum attempts. A remote attacker can perform a denial of service attack.

Note, the vulnerability exists due to an incomplete fix for #VU107155 (CVE-2025-31498).

Mitigation

Install updates from vendor's website.

Vulnerable software versions

c-ares: 1.32.3 - 1.34.5

CPE2.3

• cpe:2.3:a:c-ares_haxx_se:c-ares:1.32.3:*:*:*:*:*:*:*
• cpe:2.3:a:c-ares_haxx_se:c-ares:1.33.0:*:*:*:*:*:*:*
• cpe:2.3:a:c-ares_haxx_se:c-ares:1.33.1:*:*:*:*:*:*:*

External links

https://github.com/c-ares/c-ares/security/advisories/GHSA-jq53-42q6-pqr5
https://github.com/c-ares/c-ares/commit/714bf5675c541bd1e668a8db8e67ce012651e618

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.