Linux: Use After Free
CVE-2022-50408 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 1613a7b24f1a7467cb727ba3ec77c9a808383560, d79f4d903e14dde822c60b5fd3bedc5a289d25df, 49c742afd60f552fce7799287080db02bffe1db2 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 0.16% 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 1613a7b24f1a7467cb727ba3ec77c9a808383560 or d79f4d903e14dde822c60b5fd3bedc5a289d25df or 49c742afd60f552fce7799287080db02bffe1db2 or e01d96494a9de0f48b1167f0494f6d929fa773ed, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.14.296 or 4.19.262 or 5.4.220 or 5.10.150, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | b1a2a41126fc582a3d5613aa2d3e632b2eb1a2c4 up to, but not including, 1613a7b24f1a7467cb727ba3ec77c9a808383560; b1a2a41126fc582a3d5613aa2d3e632b2eb1a2c4 up to, but not including, d79f4d903e14dde822c60b5fd3bedc5a289d25df; b1a2a41126fc582a3d5613aa2d3e632b2eb1a2c4 up to, but not including, 49c742afd60f552fce7799287080db02bffe1db2; b1a2a41126fc582a3d5613aa2d3e632b2eb1a2c4 up to, but not including, e01d96494a9de0f48b1167f0494f6d929fa773ed; b1a2a41126fc582a3d5613aa2d3e632b2eb1a2c4 up to, but not including, 232d59eca07f6ea27307022a33d226aff373bd02; b1a2a41126fc582a3d5613aa2d3e632b2eb1a2c4 up to, but not including, 27574a3f421c3a1694d0207f37c6bbf23d66978e; b1a2a41126fc582a3d5613aa2d3e632b2eb1a2c4 up to, but not including, c369836cff98d3877f98c98e15c0151462812d96; b1a2a41126fc582a3d5613aa2d3e632b2eb1a2c4 up to, but not including, 3f42faf6db431e04bf942d2ebe3ae88975723478; and 1 more ranges | 1613a7b24f1a7467cb727ba3ec77c9a808383560, d79f4d903e14dde822c60b5fd3bedc5a289d25df, 49c742afd60f552fce7799287080db02bffe1db2, e01d96494a9de0f48b1167f0494f6d929fa773ed, 232d59eca07f6ea27307022a33d226aff373bd02, 27574a3f421c3a1694d0207f37c6bbf23d66978e |
| Linux | Linux Kernel | before 4.14.296; 4.15 up to, but not including, 4.19.262; 4.20 up to, but not including, 5.4.220; 5.5 up to, but not including, 5.10.150; 5.11 up to, but not including, 5.15.75; 5.16 up to, but not including, 5.19.17; 6.0 up to, but not including, 6.0.3 | 4.14.296, 4.19.262, 5.4.220, 5.10.150, 5.15.75, 5.19.17 |
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.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: fix use-after-free bug in brcmf_netdev_start_xmit() > ret = brcmf_proto_tx_queue_data(drvr, ifp->ifidx, skb); may be schedule, and then complete before the line > ndev->stats.tx_bytes += skb->len; [ 46.912801] ================================================================== [ 46.920552] BUG: KASAN: use-after-free in brcmf_netdev_start_xmit+0x718/0x8c8 [brcmfmac] [ 46.928673] Read of size 4 at addr ffffff803f5882e8 by task systemd-resolve/328 [ 46.935991] [ 46.937514] CPU: 1 PID: 328 Comm: systemd-resolve Tainted: G O 5.4.199-[REDACTED] #1 [ 46.947255] Hardware name: [REDACTED] [ 46.954568] Call trace: [ 46.957037] dump_backtrace+0x0/0x2b8 [ 46.960719] show_stack+0x24/0x30 [ 46.964052] dump_stack+0x128/0x194 [ 46.967557] print_address_description.isra.0+0x64/0x380 [ 46.972877] __kasan_report+0x1d4/0x240 [ 46.976723] kasan_report+0xc/0x18 [ 46.980138] __asan_report_load4_noabort+0x18/0x20 [ 46.985027] brcmf_netdev_start_xmit+0x718/0x8c8 [brcmfmac] [ 46.990613] dev_hard_start_xmit+0x1bc/0xda0 [ 46.994894] sch_direct_xmit+0x198/0xd08 [ 46.998827] __qdisc_run+0x37c/0x1dc0 [ 47.002500] __dev_queue_xmit+0x1528/0x21f8 [ 47.006692] dev_queue_xmit+0x24/0x30 [ 47.010366] neigh_resolve_output+0x37c/0x678 [ 47.014734] ip_finish_output2+0x598/0x2458 [ 47.018927] __ip_finish_output+0x300/0x730 [ 47.023118] ip_output+0x2e0/0x430 [ 47.026530] ip_local_out+0x90/0x140 [ 47.030117] igmpv3_sendpack+0x14c/0x228 [ 47.034049] igmpv3_send_cr+0x384/0x6b8 [ 47.037895] igmp_ifc_timer_expire+0x4c/0x118 [ 47.042262] call_timer_fn+0x1cc/0xbe8 [ 47.046021] __run_timers+0x4d8/0xb28 [ 47.049693] run_timer_softirq+0x24/0x40 [ 47.053626] __do_softirq+0x2c0/0x117c [ 47.057387] irq_exit+0x2dc/0x388 [ 47.060715] __handle_domain_irq+0xb4/0x158 [ 47.064908] gic_handle_irq+0x58/0xb0 [ 47.068581] el0_irq_naked+0x50/0x5c [ 47.072162] [ 47.073665] Allocated by task 328: [ 47.077083] save_stack+0x24/0xb0 [ 47.080410] __kasan_kmalloc.isra.0+0xc0/0xe0 [ 47.084776] kasan_slab_alloc+0x14/0x20 [ 47.088622] kmem_cache_alloc+0x15c/0x468 [ 47.092643] __alloc_skb+0xa4/0x498 [ 47.096142] igmpv3_newpack+0x158/0xd78 [ 47.099987] add_grhead+0x210/0x288 [ 47.103485] add_grec+0x6b0/0xb70 [ 47.106811] igmpv3_send_cr+0x2e0/0x6b8 [ 47.110657] igmp_ifc_timer_expire+0x4c/0x118 [ 47.115027] call_timer_fn+0x1cc/0xbe8 [ 47.118785] __run_timers+0x4d8/0xb28 [ 47.122457] run_timer_softirq+0x24/0x40 [ 47.126389] __do_softirq+0x2c0/0x117c [ 47.130142] [ 47.131643] Freed by task 180: [ 47.134712] save_stack+0x24/0xb0 [ 47.138041] __kasan_slab_free+0x108/0x180 [ 47.142146] kasan_slab_free+0x10/0x18 [ 47.145904] slab_free_freelist_hook+0xa4/0x1b0 [ 47.150444] kmem_cache_free+0x8c/0x528 [ 47.154292] kfree_skbmem+0x94/0x108 [ 47.157880] consume_skb+0x10c/0x5a8 [ 47.161466] __dev_kfree_skb_any+0x88/0xa0 [ 47.165598] brcmu_pkt_buf_free_skb+0x44/0x68 [brcmutil] [ 47.171023] brcmf_txfinalize+0xec/0x190 [brcmfmac] [ 47.176016] brcmf_proto_bcdc_txcomplete+0x1c0/0x210 [brcmfmac] [ 47.182056] brcmf_sdio_sendfromq+0x8dc/0x1e80 [brcmfmac] [ 47.187568] brcmf_sdio_dpc+0xb48/0x2108 [brcmfmac] [ 47.192529] brcmf_sdio_dataworker+0xc8/0x238 [brcmfmac] [ 47.197859] process_one_work+0x7fc/0x1a80 [ 47.201965] worker_thread+0x31c/0xc40 [ 47.205726] kthread+0x2d8/0x370 [ 47.208967] ret_from_fork+0x10/0x18 [ 47.212546] [ 47.214051] The buggy address belongs to the object at ffffff803f588280 [ 47.214051] which belongs to the cache skbuff_head_cache of size 208 [ 47.227086] The buggy address is located 104 bytes inside of [ 47.227086] 208-byte region [ffffff803f588280, ffffff803f588350) [ 47.238814] The buggy address belongs to the page: [ 47.243618] page:ffffffff00dd6200 refcount:1 mapcou ---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: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/1613a7b24f1a7467cb727ba3ec77c9a808383560
- git.kernel.org/stable/c/232d59eca07f6ea27307022a33d226aff373bd02
- git.kernel.org/stable/c/27574a3f421c3a1694d0207f37c6bbf23d66978e
- git.kernel.org/stable/c/3f42faf6db431e04bf942d2ebe3ae88975723478
- git.kernel.org/stable/c/49c742afd60f552fce7799287080db02bffe1db2
- git.kernel.org/stable/c/c369836cff98d3877f98c98e15c0151462812d96
- git.kernel.org/stable/c/d79f4d903e14dde822c60b5fd3bedc5a289d25df
- git.kernel.org/stable/c/e01d96494a9de0f48b1167f0494f6d929fa773ed
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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