Summary
Michał Majchrowicz and Marcin Wyczechowski discovered that libevent
incorrectly handled certain DNS responses. A remote attacker could possibly
use this issue to cause a denial of service or execute arbitrary code.
(CVE-2026-63387)
It was discovered that libevent incorrectly handled certain connections. A
local attacker could possibly use this issue to cause a denial of service
or execute arbitrary code. This issue only affected Ubuntu 18.04 LTS,
Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS.
(CVE-2026-63388)
Fixed packages 7
| Release | Package | Fixed in |
|---|---|---|
| Ubuntu · 22.04 LTS 22.04:LTS | libevent | 2.1.12-stable-1ubuntu0.2 |
| Ubuntu · 24.04 LTS 24.04:LTS | libevent | 2.1.12-stable-9ubuntu2.2 |
| Ubuntu · 26.04 LTS 26.04:LTS | libevent | 2.1.12-stable-10ubuntu0.2 |
| Ubuntu · Pro 14.04 LTS Pro:14.04:LTS | libevent | 2.0.21-stable-1ubuntu1.14.04.2+esm2 |
| Ubuntu · Pro 16.04 LTS Pro:16.04:LTS | libevent | 2.0.21-stable-2ubuntu0.16.04.1+esm2 |
| Ubuntu · Pro 18.04 LTS Pro:18.04:LTS | libevent | 2.1.8-stable-4ubuntu0.1~esm2 |
| Ubuntu · Pro 20.04 LTS Pro:20.04:LTS | libevent | 2.1.11-stable-1ubuntu0.1~esm2 |
Vulnerabilities 2
-
High 8.4
Libevent: Heap out-of-bounds write in bufferevent_socket_set_conn_address_ reachable via AF_UNIX accept
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_add…
-
High 7.0
Libevent: Off-by-one stack buffer overflow in dnsname_to_labels via crafted DNS server response
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an off-by-one stack buffer overflow in evdns.c when dnsname_to_labels formats a name-bearing DNS record at the end of the 64 KB stack buffer allocated by evdns_server_req…