vulnerability

Ubuntu: USN-7477-1 (CVE-2025-31498): c-ares vulnerability

Severity
8
CVSS
(AV:N/AC:L/Au:N/C:N/I:N/A:C)
Published
Apr 8, 2025
Added
May 6, 2025
Modified
May 6, 2025

Description

c-ares is an asynchronous resolver library. From 1.32.3 through 1.34.4, there is a use-after-free in read_answers() when process_answer() may re-enqueue a query either due to a DNS Cookie Failure or when the upstream server does not properly support EDNS, or possibly on TCP queries if the remote closed the connection immediately after a response. If there was an issue trying to put that new transaction on the wire, it would close the connection handle, but read_answers() was still expecting the connection handle to be available to possibly dequeue other responses. In theory a remote attacker might be able to trigger this by flooding the target with ICMP UNREACHABLE packets if they also control the upstream nameserver and can return a result with one of those conditions, this has been untested. Otherwise only a local attacker might be able to change system behavior to make send()/write() return a failure condition. This vulnerability is fixed in 1.34.5.

Solution

ubuntu-upgrade-libcares2
Title
NEW

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