Linux Kernel up to 6.1.4 net mm/slab_common.c tcindex_change memory leak

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5.0	$0-$5k	0.00

Summaryinfo

A vulnerability categorized as critical has been discovered in Linux Kernel up to 5.4.228/5.10.162/5.15.86/6.0.18/6.1.4. The affected element is the function tcindex_change of the file mm/slab_common.c of the component net. Such manipulation leads to memory leak. This vulnerability is documented as CVE-2022-50396. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.4.228/5.10.162/5.15.86/6.0.18/6.1.4. It has been rated as critical. Affected by this issue is the function tcindex_change of the file mm/slab_common.c of the component net. The manipulation with an unknown input leads to a memory leak vulnerability. Using CWE to declare the problem leads to CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net: sched: fix memory leak in tcindex_set_parms Syzkaller reports a memory leak as follows: ==================================== BUG: memory leak unreferenced object 0xffff88810c287f00 (size 256): comm "syz-executor105", pid 3600, jiffies 4294943292 (age 12.990s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff814cf9f0>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046 [<ffffffff839c9e07>] kmalloc include/linux/slab.h:576 [inline] [<ffffffff839c9e07>] kmalloc_array include/linux/slab.h:627 [inline] [<ffffffff839c9e07>] kcalloc include/linux/slab.h:659 [inline] [<ffffffff839c9e07>] tcf_exts_init include/net/pkt_cls.h:250 [inline] [<ffffffff839c9e07>] tcindex_set_parms+0xa7/0xbe0 net/sched/cls_tcindex.c:342 [<ffffffff839caa1f>] tcindex_change+0xdf/0x120 net/sched/cls_tcindex.c:553 [<ffffffff8394db62>] tc_new_tfilter+0x4f2/0x1100 net/sched/cls_api.c:2147 [<ffffffff8389e91c>] rtnetlink_rcv_msg+0x4dc/0x5d0 net/core/rtnetlink.c:6082 [<ffffffff839eba67>] netlink_rcv_skb+0x87/0x1d0 net/netlink/af_netlink.c:2540 [<ffffffff839eab87>] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] [<ffffffff839eab87>] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345 [<ffffffff839eb046>] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921 [<ffffffff8383e796>] sock_sendmsg_nosec net/socket.c:714 [inline] [<ffffffff8383e796>] sock_sendmsg+0x56/0x80 net/socket.c:734 [<ffffffff8383eb08>] ____sys_sendmsg+0x178/0x410 net/socket.c:2482 [<ffffffff83843678>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536 [<ffffffff838439c5>] __sys_sendmmsg+0x105/0x330 net/socket.c:2622 [<ffffffff83843c14>] __do_sys_sendmmsg net/socket.c:2651 [inline] [<ffffffff83843c14>] __se_sys_sendmmsg net/socket.c:2648 [inline] [<ffffffff83843c14>] __x64_sys_sendmmsg+0x24/0x30 net/socket.c:2648 [<ffffffff84605fd5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff84605fd5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd ==================================== Kernel uses tcindex_change() to change an existing filter properties. Yet the problem is that, during the process of changing, if `old_r` is retrieved from `p->perfect`, then kernel uses tcindex_alloc_perfect_hash() to newly allocate filter results, uses tcindex_filter_result_init() to clear the old filter result, without destroying its tcf_exts structure, which triggers the above memory leak. To be more specific, there are only two source for the `old_r`, according to the tcindex_lookup(). `old_r` is retrieved from `p->perfect`, or `old_r` is retrieved from `p->h`. * If `old_r` is retrieved from `p->perfect`, kernel uses tcindex_alloc_perfect_hash() to newly allocate the filter results. Then `r` is assigned with `cp->perfect + handle`, which is newly allocated. So condition `old_r && old_r != r` is true in this situation, and kernel uses tcindex_filter_result_init() to clear the old filter result, without destroying its tcf_exts structure * If `old_r` is retrieved from `p->h`, then `p->perfect` is NULL according to the tcindex_lookup(). Considering that `cp->h` is directly copied from `p->h` and `p->perfect` is NULL, `r` is assigned with `tcindex_lookup(cp, handle)`, whose value should be the same as `old_r`, so condition `old_r && old_r != r` is false in this situation, kernel ignores using tcindex_filter_result_init() to clear the old filter result. So only when `old_r` is retrieved from `p->perfect` does kernel use tcindex_filter_result_init() to clear the old filter result, which triggers the above memory leak. Considering that there already exists a tc_filter_wq workqueue to destroy the old tcindex_d ---truncated---

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2022-50396 since 09/17/2025. The exploitation is known to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 265574 (Linux Distros Unpatched Vulnerability : CVE-2022-50396), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.4.229, 5.10.163, 5.15.87, 6.0.19 or 6.1.5 eliminates this vulnerability. Applying the patch 55ac68b53f1cea1926ee2313afc5d66b91daad71/b314f6c3512108d7a656c5caf07c82d1bbbdc0f1/6c55953e232ea668731091d111066521f3b7719b/c4de6057e7c6654983acb63d939d26ac0d7bbf39/facc4405e8b7407e03216207b1d1d640127de0c8/399ab7fe0fa0d846881685fd4e57e9a8ef7559f7 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (265574) and CERT Bund (WID-SEC-2025-2092). Once again VulDB remains the best source for vulnerability data.

Affected

• Amazon Linux 2
• Red Hat Enterprise Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel
• Dell Secure Connect Gateway
• IBM QRadar SIEM

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.4.228
• 5.10.162
• 5.15.0
• 5.15.1
• 5.15.2
• 5.15.3
• 5.15.4
• 5.15.5
• 5.15.6
• 5.15.7
• 5.15.8
• 5.15.9
• 5.15.10
• 5.15.11
• 5.15.12
• 5.15.13
• 5.15.14
• 5.15.15
• 5.15.16
• 5.15.17
• 5.15.18
• 5.15.19
• 5.15.20
• 5.15.21
• 5.15.22
• 5.15.23
• 5.15.24
• 5.15.25
• 5.15.26
• 5.15.27
• 5.15.28
• 5.15.29
• 5.15.30
• 5.15.31
• 5.15.32
• 5.15.33
• 5.15.34
• 5.15.35
• 5.15.36
• 5.15.37
• 5.15.38
• 5.15.39
• 5.15.40
• 5.15.41
• 5.15.42
• 5.15.43
• 5.15.44
• 5.15.45
• 5.15.46
• 5.15.47
• 5.15.48
• 5.15.49
• 5.15.50
• 5.15.51
• 5.15.52
• 5.15.53
• 5.15.54
• 5.15.55
• 5.15.56
• 5.15.57
• 5.15.58
• 5.15.59
• 5.15.60
• 5.15.61
• 5.15.62
• 5.15.63
• 5.15.64
• 5.15.65
• 5.15.66
• 5.15.67
• 5.15.68
• 5.15.69
• 5.15.70
• 5.15.71
• 5.15.72
• 5.15.73
• 5.15.74
• 5.15.75
• 5.15.76
• 5.15.77
• 5.15.78
• 5.15.79
• 5.15.80
• 5.15.81
• 5.15.82
• 5.15.83
• 5.15.84
• 5.15.85
• 5.15.86
• 6.0.0
• 6.0.1
• 6.0.2
• 6.0.3
• 6.0.4
• 6.0.5
• 6.0.6
• 6.0.7
• 6.0.8
• 6.0.9
• 6.0.10
• 6.0.11
• 6.0.12
• 6.0.13
• 6.0.14
• 6.0.15
• 6.0.16
• 6.0.17
• 6.0.18
• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
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CPE 2.2info

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CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory leak
CWE: CWE-401 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 265574
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2022-50396

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.4.229/5.10.163/5.15.87/6.0.19/6.1.5
Patch: 55ac68b53f1cea1926ee2313afc5d66b91daad71/b314f6c3512108d7a656c5caf07c82d1bbbdc0f1/6c55953e232ea668731091d111066521f3b7719b/c4de6057e7c6654983acb63d939d26ac0d7bbf39/facc4405e8b7407e03216207b1d1d640127de0c8/399ab7fe0fa0d846881685fd4e57e9a8ef7559f7

Timelineinfo

09/17/2025 CVE reserved
09/18/2025 +1 days Advisory disclosed
09/18/2025 +0 days VulDB entry created
12/11/2025 +84 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2022-50396 (🔒)
GCVE (CVE): GCVE-0-2022-50396
GCVE (VulDB): GCVE-100-324836
CERT Bund: WID-SEC-2025-2092 - Linux Kernel: Mehrere Schwachstellen erm&ouml;glichen Denial of Service

Entryinfo

Created: 09/18/2025 16:21
Updated: 12/11/2025 21:47
Changes: 09/18/2025 16:21 (60), 09/19/2025 20:04 (7), 09/20/2025 21:53 (2), 11/29/2025 13:52 (1), 12/11/2025 21:47 (12)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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