Linux: Use After Free
CVE-2024-46782 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 43d34110882b97ba1ec66cc8234b18983efb9abf, dcaf4e2216824839d26727a15b638c6a677bd9fc, 93ee345ba349922834e6a9d1dadabaedcc12dce6 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.24% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 43d34110882b97ba1ec66cc8234b18983efb9abf or dcaf4e2216824839d26727a15b638c6a677bd9fc or 93ee345ba349922834e6a9d1dadabaedcc12dce6 or bda4d84ac0d5421b346faee720011f58bdb99673, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.19.322 or 5.4.284 or 5.10.226 or 5.15.167, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 7f00feaf107645d95a6d87e99b4d141ac0a08efd up to, but not including, 43d34110882b97ba1ec66cc8234b18983efb9abf; 7f00feaf107645d95a6d87e99b4d141ac0a08efd up to, but not including, dcaf4e2216824839d26727a15b638c6a677bd9fc; 7f00feaf107645d95a6d87e99b4d141ac0a08efd up to, but not including, 93ee345ba349922834e6a9d1dadabaedcc12dce6; 7f00feaf107645d95a6d87e99b4d141ac0a08efd up to, but not including, bda4d84ac0d5421b346faee720011f58bdb99673; 7f00feaf107645d95a6d87e99b4d141ac0a08efd up to, but not including, 925c18a7cff93d8a4320d652351294ff7d0ac93c; 7f00feaf107645d95a6d87e99b4d141ac0a08efd up to, but not including, 18a5a16940464b301ea91bf5da3a324aedb347b2; 7f00feaf107645d95a6d87e99b4d141ac0a08efd up to, but not including, 47abd8adddbc0aecb8f231269ef659148d5dabe4; 7f00feaf107645d95a6d87e99b4d141ac0a08efd up to, but not including, 031ae72825cef43e4650140b800ad58bf7a6a466; and 1 more ranges | 43d34110882b97ba1ec66cc8234b18983efb9abf, dcaf4e2216824839d26727a15b638c6a677bd9fc, 93ee345ba349922834e6a9d1dadabaedcc12dce6, bda4d84ac0d5421b346faee720011f58bdb99673, 925c18a7cff93d8a4320d652351294ff7d0ac93c, 18a5a16940464b301ea91bf5da3a324aedb347b2 |
| Linux | Linux Kernel | 4.5 up to, but not including, 4.19.322; 4.20 up to, but not including, 5.4.284; 5.5 up to, but not including, 5.10.226; 5.11 up to, but not including, 5.15.167; 5.16 up to, but not including, 6.1.110; 6.2 up to, but not including, 6.6.51; 6.7 up to, but not including, 6.10.10; 6.11 | 4.19.322, 5.4.284, 5.10.226, 5.15.167, 6.1.110, 6.6.51 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: ila: call nf_unregister_net_hooks() sooner syzbot found an use-after-free Read in ila_nf_input [1] Issue here is that ila_xlat_exit_net() frees the rhashtable, then call nf_unregister_net_hooks(). It should be done in the reverse way, with a synchronize_rcu(). This is a good match for a pre_exit() method. [1] BUG: KASAN: use-after-free in rht_key_hashfn include/linux/rhashtable.h:159 [inline] BUG: KASAN: use-after-free in __rhashtable_lookup include/linux/rhashtable.h:604 [inline] BUG: KASAN: use-after-free in rhashtable_lookup include/linux/rhashtable.h:646 [inline] BUG: KASAN: use-after-free in rhashtable_lookup_fast+0x77a/0x9b0 include/linux/rhashtable.h:672 Read of size 4 at addr ffff888064620008 by task ksoftirqd/0/16 CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.11.0-rc4-syzkaller-00238-g2ad6d23f465a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 rht_key_hashfn include/linux/rhashtable.h:159 [inline] __rhashtable_lookup include/linux/rhashtable.h:604 [inline] rhashtable_lookup include/linux/rhashtable.h:646 [inline] rhashtable_lookup_fast+0x77a/0x9b0 include/linux/rhashtable.h:672 ila_lookup_wildcards net/ipv6/ila/ila_xlat.c:132 [inline] ila_xlat_addr net/ipv6/ila/ila_xlat.c:652 [inline] ila_nf_input+0x1fe/0x3c0 net/ipv6/ila/ila_xlat.c:190 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312 __netif_receive_skb_one_core net/core/dev.c:5661 [inline] __netif_receive_skb+0x1ea/0x650 net/core/dev.c:5775 process_backlog+0x662/0x15b0 net/core/dev.c:6108 __napi_poll+0xcb/0x490 net/core/dev.c:6772 napi_poll net/core/dev.c:6841 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6963 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554 run_ksoftirqd+0xca/0x130 kernel/softirq.c:928 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x64620 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: 0xbfffffff(buddy) raw: 00fff00000000000 ffffea0000959608 ffffea00019d9408 0000000000000000 raw: 0000000000000000 0000000000000003 00000000bfffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 3, migratetype Unmovable, gfp_mask 0x52dc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_ZERO), pid 5242, tgid 5242 (syz-executor), ts 73611328570, free_ts 618981657187 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493 prep_new_page mm/page_alloc.c:1501 [inline] get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3439 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4695 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] ___kmalloc_large_node+0x8b/0x1d0 mm/slub.c:4103 __kmalloc_large_node_noprof+0x1a/0x80 mm/slub.c:4130 __do_kmalloc_node mm/slub.c:4146 [inline] __kmalloc_node_noprof+0x2d2/0x440 mm/slub.c:4164 __kvmalloc_node_noprof+0x72/0x190 mm/util.c:650 bucket_table_alloc lib/rhashtable.c:186 [inline] rhashtable_init_noprof+0x534/0xa60 lib/rhashtable.c:1071 ila_xlat_init_net+0xa0/0x110 net/ipv6/ila/ila_xlat.c:613 ops_ini ---truncated---
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/031ae72825cef43e4650140b800ad58bf7a6a466
- git.kernel.org/stable/c/18a5a16940464b301ea91bf5da3a324aedb347b2
- git.kernel.org/stable/c/43d34110882b97ba1ec66cc8234b18983efb9abf
- git.kernel.org/stable/c/47abd8adddbc0aecb8f231269ef659148d5dabe4
- git.kernel.org/stable/c/925c18a7cff93d8a4320d652351294ff7d0ac93c
- git.kernel.org/stable/c/93ee345ba349922834e6a9d1dadabaedcc12dce6
- git.kernel.org/stable/c/bda4d84ac0d5421b346faee720011f58bdb99673
- git.kernel.org/stable/c/dcaf4e2216824839d26727a15b638c6a677bd9fc
Other references
Recent Use After Free vulnerabilities
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