File avahi-CVE-2025-68276.patch of Package avahi
From 2d48e42d44a183f26a4d12d1f5d41abb9b7c6355 Mon Sep 17 00:00:00 2001
From: Evgeny Vereshchagin <evvers@ya.ru>
Date: Wed, 17 Dec 2025 08:11:23 +0000
Subject: [PATCH] core: refuse to create wide-area record browsers when
wide-area is off
It fixes a bug where it was possible for unprivileged local users to
crash avahi-daemon (with wide-area disabled) by creating record browsers
with the AVAHI_LOOKUP_USE_WIDE_AREA flag set via D-Bus (either by calling
the RecordBrowserNew method directly or by creating hostname/address/service
resolvers/browsers that create those browsers internally themselves).
```
$ gdbus call --system --dest org.freedesktop.Avahi --object-path / --method org.freedesktop.Avahi.Server.ResolveHostName -- -1 -1 yo.local -1 1
Error: GDBus.Error:org.freedesktop.DBus.Error.NoReply: Message recipient disconnected from message bus without replying
```
```
dbus-protocol.c: interface=org.freedesktop.Avahi.Server, path=/, member=ResolveHostName
avahi-daemon: wide-area.c:725: avahi_wide_area_scan_cache: Assertion `e' failed.
==307948==
==307948== Process terminating with default action of signal 6 (SIGABRT)
==307948== at 0x4B3630C: __pthread_kill_implementation (pthread_kill.c:44)
==307948== by 0x4ADF921: raise (raise.c:26)
==307948== by 0x4AC74AB: abort (abort.c:77)
==307948== by 0x4AC741F: __assert_fail_base.cold (assert.c:118)
==307948== by 0x48D8B85: avahi_wide_area_scan_cache (wide-area.c:725)
==307948== by 0x48C8953: lookup_scan_cache (browse.c:351)
==307948== by 0x48C8B1B: lookup_go (browse.c:386)
==307948== by 0x48C9148: defer_callback (browse.c:516)
==307948== by 0x48AEA0E: expiration_event (timeeventq.c:94)
==307948== by 0x489D3AE: timeout_callback (simple-watch.c:447)
==307948== by 0x489D787: avahi_simple_poll_dispatch (simple-watch.c:563)
==307948== by 0x489D91E: avahi_simple_poll_iterate (simple-watch.c:605)
==307948==
```
wide-area has been disabled by default since
9c4214146738146e454f098264690e8e884c39bd (v0.9-rc2).
https://github.com/avahi/avahi/security/advisories/GHSA-mhf3-865v-g5rc
---
avahi-core/browse.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/avahi-core/browse.c b/avahi-core/browse.c
index 0afeba7..d7d541b 100644
--- a/avahi-core/browse.c
+++ b/avahi-core/browse.c
@@ -583,6 +583,11 @@ AvahiSRecordBrowser *avahi_s_record_browser_prepare(
AVAHI_CHECK_VALIDITY_RETURN_NULL(server, AVAHI_FLAGS_VALID(flags, AVAHI_LOOKUP_USE_WIDE_AREA|AVAHI_LOOKUP_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS);
AVAHI_CHECK_VALIDITY_RETURN_NULL(server, !(flags & AVAHI_LOOKUP_USE_WIDE_AREA) || !(flags & AVAHI_LOOKUP_USE_MULTICAST), AVAHI_ERR_INVALID_FLAGS);
+ if ((flags & AVAHI_LOOKUP_USE_WIDE_AREA) && !server->wide_area_lookup_engine) {
+ avahi_server_set_errno(server, AVAHI_ERR_NOT_SUPPORTED);
+ return NULL;
+ }
+
if (!(b = avahi_new(AvahiSRecordBrowser, 1))) {
avahi_server_set_errno(server, AVAHI_ERR_NO_MEMORY);
return NULL;
--
2.49.0
