{"id":"DEBIAN-CVE-2024-56655","details":"In the Linux kernel, the following vulnerability has been resolved:  netfilter: nf_tables: do not defer rule destruction via call_rcu  nf_tables_chain_destroy can sleep, it can't be used from call_rcu callbacks.  Moreover, nf_tables_rule_release() is only safe for error unwinding, while transaction mutex is held and the to-be-desroyed rule was not exposed to either dataplane or dumps, as it deactives+frees without the required synchronize_rcu() in-between.  nft_rule_expr_deactivate() callbacks will change -\u003euse counters of other chains/sets, see e.g. nft_lookup .deactivate callback, these must be serialized via transaction mutex.  Also add a few lockdep asserts to make this more explicit.  Calling synchronize_rcu() isn't ideal, but fixing this without is hard and way more intrusive.  As-is, we can get:  WARNING: .. net/netfilter/nf_tables_api.c:5515 nft_set_destroy+0x.. Workqueue: events nf_tables_trans_destroy_work RIP: 0010:nft_set_destroy+0x3fe/0x5c0 Call Trace:  \u003cTASK\u003e  nf_tables_trans_destroy_work+0x6b7/0xad0  process_one_work+0x64a/0xce0  worker_thread+0x613/0x10d0  In case the synchronize_rcu becomes an issue, we can explore alternatives.  One way would be to allocate nft_trans_rule objects + one nft_trans_chain object, deactivate the rules + the chain and then defer the freeing to the nft destroy workqueue.  We'd still need to keep the synchronize_rcu path as a fallback to handle -ENOMEM corner cases though.","modified":"2026-09-15T09:03:17.189070548Z","published":"2024-12-27T15:15:25.343Z","upstream":["CVE-2024-56655"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2024-56655"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.6-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2024-56655.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.6-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2024-56655.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}