Linux Kernel up to 6.5.3 kcm kcm_sendmsg memory leak

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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability categorized as critical has been discovered in Linux Kernel up to 6.5.3. This vulnerability affects the function kcm_sendmsg of the component kcm. The manipulation results in memory leak. This vulnerability is identified as CVE-2023-53825. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.5.3. It has been classified as critical. Affected is the function kcm_sendmsg of the component kcm. The manipulation with an unknown input leads to a memory leak vulnerability. CWE is classifying the issue as CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: kcm: Fix error handling for SOCK_DGRAM in kcm_sendmsg(). syzkaller found a memory leak in kcm_sendmsg(), and commit c821a88bd720 ("kcm: Fix memory leak in error path of kcm_sendmsg()") suppressed it by updating kcm_tx_msg(head)->last_skb if partial data is copied so that the following sendmsg() will resume from the skb. However, we cannot know how many bytes were copied when we get the error. Thus, we could mess up the MSG_MORE queue. When kcm_sendmsg() fails for SOCK_DGRAM, we should purge the queue as we do so for UDP by udp_flush_pending_frames(). Even without this change, when the error occurred, the following sendmsg() resumed from a wrong skb and the queue was messed up. However, we have yet to get such a report, and only syzkaller stumbled on it. So, this can be changed safely. Note this does not change SOCK_SEQPACKET behaviour.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2023-53825 since 12/09/2025. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 278544 (Linux Distros Unpatched Vulnerability : CVE-2023-53825), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.14.326, 4.19.295, 5.4.257, 5.10.195, 5.15.132, 6.1.54 or 6.5.4 eliminates this vulnerability. Applying the patch 21b467735b0888a8daa048f83d3b9b50fdab71ce/d4b8f380b0a041ee6a84fdac14127d8fe1dcad7b/1ce8362b4ac6b8e65fd04a22ea37ec776ee1ec5b/2e18493c421428a936946c452461b8e979088f17/55d2e7c1ab8eaa7b62575b8a4194132795d1f9fc/e5b28ce127a690f3acc49a6a342e6c9442c9edd6/992b2ac783aad360b98ed9d4686e86176a20f6f1/a22730b1b4bf437c6bbfdeff5feddf54be4aeada 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 (278544) and CERT Bund (WID-SEC-2025-2765). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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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: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 278544
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2023-53825

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 4.14.326/4.19.295/5.4.257/5.10.195/5.15.132/6.1.54/6.5.4
Patch: 21b467735b0888a8daa048f83d3b9b50fdab71ce/d4b8f380b0a041ee6a84fdac14127d8fe1dcad7b/1ce8362b4ac6b8e65fd04a22ea37ec776ee1ec5b/2e18493c421428a936946c452461b8e979088f17/55d2e7c1ab8eaa7b62575b8a4194132795d1f9fc/e5b28ce127a690f3acc49a6a342e6c9442c9edd6/992b2ac783aad360b98ed9d4686e86176a20f6f1/a22730b1b4bf437c6bbfdeff5feddf54be4aeada

Timelineinfo

12/09/2025 Advisory disclosed
12/09/2025 +0 days CVE reserved
12/09/2025 +0 days VulDB entry created
03/30/2026 +110 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2023-53825 (🔒)
GCVE (CVE): GCVE-0-2023-53825
GCVE (VulDB): GCVE-100-334986
CERT Bund: WID-SEC-2025-2765 - Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 12/09/2025 09:15
Updated: 03/30/2026 01:53
Changes: 12/09/2025 09:15 (59), 12/12/2025 23:43 (2), 03/30/2026 01:53 (7)
Complete: 🔍
Cache ID: 216:E83:103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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