Linux Kernel up to 6.3.4 net net/core/skbuff.c cdc_ncm_check_tx_max allocation of resources

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4.9	$0-$5k	0.00

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.3.4. The impacted element is the function cdc_ncm_check_tx_max of the file net/core/skbuff.c of the component net. The manipulation results in allocation of resources. This vulnerability is cataloged as CVE-2023-53667. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.3.4. It has been classified as critical. Affected is the function cdc_ncm_check_tx_max of the file net/core/skbuff.c of the component net. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net: cdc_ncm: Deal with too low values of dwNtbOutMaxSize Currently in cdc_ncm_check_tx_max(), if dwNtbOutMaxSize is lower than the calculated "min" value, but greater than zero, the logic sets tx_max to dwNtbOutMaxSize. This is then used to allocate a new SKB in cdc_ncm_fill_tx_frame() where all the data is handled. For small values of dwNtbOutMaxSize the memory allocated during alloc_skb(dwNtbOutMaxSize, GFP_ATOMIC) will have the same size, due to how size is aligned at alloc time: size = SKB_DATA_ALIGN(size); size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); Thus we hit the same bug that we tried to squash with commit 2be6d4d16a084 ("net: cdc_ncm: Allow for dwNtbOutMaxSize to be unset or zero") Low values of dwNtbOutMaxSize do not cause an issue presently because at alloc_skb() time more memory (512b) is allocated than required for the SKB headers alone (320b), leaving some space (512b - 320b = 192b) for CDC data (172b). However, if more elements (for example 3 x u64 = [24b]) were added to one of the SKB header structs, say 'struct skb_shared_info', increasing its original size (320b [320b aligned]) to something larger (344b [384b aligned]), then suddenly the CDC data (172b) no longer fits in the spare SKB data area (512b - 384b = 128b). Consequently the SKB bounds checking semantics fails and panics: skbuff: skb_over_panic: text:ffffffff831f755b len:184 put:172 head:ffff88811f1c6c00 data:ffff88811f1c6c00 tail:0xb8 end:0x80 dev:<NULL> ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:113! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 57 Comm: kworker/0:2 Not tainted 5.15.106-syzkaller-00249-g19c0ed55a470 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 Workqueue: mld mld_ifc_work RIP: 0010:skb_panic net/core/skbuff.c:113 [inline] RIP: 0010:skb_over_panic+0x14c/0x150 net/core/skbuff.c:118 [snip] Call Trace: <TASK> skb_put+0x151/0x210 net/core/skbuff.c:2047 skb_put_zero include/linux/skbuff.h:2422 [inline] cdc_ncm_ndp16 drivers/net/usb/cdc_ncm.c:1131 [inline] cdc_ncm_fill_tx_frame+0x11ab/0x3da0 drivers/net/usb/cdc_ncm.c:1308 cdc_ncm_tx_fixup+0xa3/0x100 Deal with too low values of dwNtbOutMaxSize, clamp it in the range [USB_CDC_NCM_NTB_MIN_OUT_SIZE, CDC_NCM_NTB_MAX_SIZE_TX]. We ensure enough data space is allocated to handle CDC data by making sure dwNtbOutMaxSize is not smaller than USB_CDC_NCM_NTB_MIN_OUT_SIZE.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2023-53667 since 10/07/2025. The exploitability is told to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 297598 (EulerOS 2.0 SP13 : kernel (EulerOS-SA-2026-1212)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.14.317, 4.19.285, 5.4.245, 5.10.181, 5.15.114, 6.1.31 or 6.3.5 eliminates this vulnerability. Applying the patch 2334ff0b343ba6ba7a6c0586fcc83992bbbc1776/bf415bfe7573596ac213b4fd1da9e62cfc9a9413/ff484163dfb61b58f23e4dbd007de1094427669c/42b78c8cc774b47023d6d16d96d54cc7015e4a07/9be921854e983a81a0aeeae5febcd87093086e46/6147745d43ff4e0d2c542e5b93e398ef0ee4db00/72d0240b0ee4794efc683975c213e4b384fea733/7e01c7f7046efc2c7c192c3619db43292b98e997 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 (297598) and CERT Bund (WID-SEC-2025-2229). Once again VulDB remains the best source for vulnerability data.

Affected

• Amazon Linux 2
• Red Hat Enterprise Linux
• SUSE Linux
• Oracle Linux
• RESF Rocky Linux
• Open Source Linux Kernel
• IBM QRadar SIEM
• Dell NetWorker

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.14.316
• 4.19.284
• 5.4.244
• 5.10.180
• 5.15.113
• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.1.20
• 6.1.21
• 6.1.22
• 6.1.23
• 6.1.24
• 6.1.25
• 6.1.26
• 6.1.27
• 6.1.28
• 6.1.29
• 6.1.30
• 6.3.0
• 6.3.1
• 6.3.2
• 6.3.3
• 6.3.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
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CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.0
VulDB Meta Temp Score: 4.9

VulDB Base Score: 4.6
VulDB Temp Score: 4.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

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

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
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Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Allocation of resources
CWE: CWE-770 / CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 297598
Nessus Name: EulerOS 2.0 SP13 : kernel (EulerOS-SA-2026-1212)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 4.14.317/4.19.285/5.4.245/5.10.181/5.15.114/6.1.31/6.3.5
Patch: 2334ff0b343ba6ba7a6c0586fcc83992bbbc1776/bf415bfe7573596ac213b4fd1da9e62cfc9a9413/ff484163dfb61b58f23e4dbd007de1094427669c/42b78c8cc774b47023d6d16d96d54cc7015e4a07/9be921854e983a81a0aeeae5febcd87093086e46/6147745d43ff4e0d2c542e5b93e398ef0ee4db00/72d0240b0ee4794efc683975c213e4b384fea733/7e01c7f7046efc2c7c192c3619db43292b98e997

Timelineinfo

10/07/2025 Advisory disclosed
10/07/2025 +0 days CVE reserved
10/07/2025 +0 days VulDB entry created
03/01/2026 +145 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2023-53667 (🔒)
GCVE (CVE): GCVE-0-2023-53667
GCVE (VulDB): GCVE-100-327444
CERT Bund: WID-SEC-2025-2229 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 10/07/2025 19:17
Updated: 03/01/2026 12:32
Changes: 10/07/2025 19:17 (60), 11/23/2025 03:34 (7), 12/26/2025 00:10 (1), 02/03/2026 10:24 (2), 02/04/2026 01:33 (12), 03/01/2026 12:32 (1)
Complete: 🔍
Cache ID: 216::103

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