In the Linux kernel, the following vulnerability has been resolved: ax25: properly unshare skbs in ax25_kiss_rcv() Bernard Pidoux reported a regression apparently caused by commit c353e8983e0d ("net: introduce per netns packet chains"). skb->dev becomes NULL and we crash in __netif_receive_skb_core(). Before above commit, different kind of bugs or corruptions could happen without a major crash. But the root cause is that ax25_kiss_rcv() can queue/mangle input skb without checking if this skb is shared or not. Many thanks to Bernard Pidoux for his help, diagnosis and tests. We had a similar issue years ago fixed with commit 7aaed57c5c28 ("phonet: properly unshare skbs in phonet_rcv()").

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Linux
  • Linux Kernel

No data.

No data.

References
Link Providers
https://git.kernel.org/stable/c/01a2984cb803f2d487b7074f9718db2bf3531f69 cve-icon cve-icon
https://git.kernel.org/stable/c/2bd0f67212908243ce88e35bf69fa77155b47b14 cve-icon cve-icon
https://git.kernel.org/stable/c/42b46684e2c78ee052d8c2ee8d9c2089233c9094 cve-icon cve-icon
https://git.kernel.org/stable/c/5b079be1b9da49ad88fc304c874d4be7085f7883 cve-icon cve-icon
https://git.kernel.org/stable/c/7d449b7a6c8ee434d10a483feed7c5c50108cf56 cve-icon cve-icon
https://git.kernel.org/stable/c/8156210d36a43e76372312c87eb5ea3dbb405a85 cve-icon cve-icon
https://git.kernel.org/stable/c/89064cf534bea4bb28c83fe6bbb26657b19dd5fe cve-icon cve-icon
https://git.kernel.org/stable/c/b1c71d674a308d2fbc83efcf88bfc4217a86aa17 cve-icon cve-icon
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html cve-icon
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html cve-icon
https://lore.kernel.org/linux-cve-announce/2025091904-CVE-2025-39848-7675@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-39848 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-39848 cve-icon
History

Mon, 03 Nov 2025 18:30:00 +0000

Type Values Removed Values Added
References

Mon, 22 Sep 2025 10:15:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Sat, 20 Sep 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Fri, 19 Sep 2025 15:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ax25: properly unshare skbs in ax25_kiss_rcv() Bernard Pidoux reported a regression apparently caused by commit c353e8983e0d ("net: introduce per netns packet chains"). skb->dev becomes NULL and we crash in __netif_receive_skb_core(). Before above commit, different kind of bugs or corruptions could happen without a major crash. But the root cause is that ax25_kiss_rcv() can queue/mangle input skb without checking if this skb is shared or not. Many thanks to Bernard Pidoux for his help, diagnosis and tests. We had a similar issue years ago fixed with commit 7aaed57c5c28 ("phonet: properly unshare skbs in phonet_rcv()").
Title ax25: properly unshare skbs in ax25_kiss_rcv()
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2025-09-19T15:26:21.403Z

Updated: 2025-11-03T17:44:06.959Z

Reserved: 2025-04-16T07:20:57.142Z

Link: CVE-2025-39848

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-09-19T16:15:43.640

Modified: 2025-11-03T18:16:50.360

Link: CVE-2025-39848

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-09-19T00:00:00Z

Links: CVE-2025-39848 - Bugzilla