Linux Kernel up to 6.17.2 io_zcrx_recv_skb buffer overflow

CVSS Meta Temp Score
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.17.2. This affects the function io_zcrx_recv_skb. Executing a manipulation can lead to buffer overflow. The identification of this vulnerability is CVE-2025-40046. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.17.2. It has been declared as critical. This vulnerability affects the function io_zcrx_recv_skb. The manipulation with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: io_uring/zcrx: fix overshooting recv limit It's reported that sometimes a zcrx request can receive more than was requested. It's caused by io_zcrx_recv_skb() adjusting desc->count for all received buffers including frag lists, but then doing recursive calls to process frag list skbs, which leads to desc->count double accounting and underflow.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2025-40046 since 04/16/2025. The exploitation appears to be easy. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 05/20/2026).

The vulnerability scanner Nessus provides a plugin with the ID 271919 (Linux Distros Unpatched Vulnerability : CVE-2025-40046), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.17.3 or 6.18-rc1 eliminates this vulnerability. Applying the patch 8bcc9eaf1b19f1a7029cba19f6bd4122b40f6c4f/09cfd3c52ea76f43b3cb15e570aeddf633d65e80 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 (271919) and CERT Bund (WID-SEC-2025-2431). Once again VulDB remains the best source for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • IBM QRadar SIEM
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • Microsoft Azure
  • Dell NetWorker
  • Dell ECS

Productinfo

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.0
VulDB Meta Temp Score: 7.6

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 271919
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-40046

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.17.3/6.18-rc1
Patch: 8bcc9eaf1b19f1a7029cba19f6bd4122b40f6c4f/09cfd3c52ea76f43b3cb15e570aeddf633d65e80

Timelineinfo

04/16/2025 CVE reserved
10/28/2025 +195 days Advisory disclosed
10/28/2025 +0 days VulDB entry created
05/20/2026 +203 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-40046 (🔒)
GCVE (CVE): GCVE-0-2025-40046
GCVE (VulDB): GCVE-100-330244
CERT Bund: WID-SEC-2025-2431 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 10/28/2025 14:34
Updated: 05/20/2026 01:45
Changes: 10/28/2025 14:34 (58), 10/29/2025 07:31 (2), 10/30/2025 05:37 (7), 10/30/2025 13:29 (1), 11/24/2025 15:14 (1), 12/22/2025 00:54 (1), 02/08/2026 16:45 (1), 02/15/2026 19:08 (1), 05/20/2026 01:45 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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