CVE-2025-23142: Linux kernel · sctp: detect and prevent references to a freed transport in sendmsg sctp_sendmsg()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1088.95~20.04.1 : patch Linux kernel soon.
Data as of 28 Oct 2026, 11:14 UTC
- Patch
- Available – fixed in 5.15.0-1088.95~20.04.1, 5.15.0-1094.103~20.04.1, 5.15.0-1087.96~20.04.2 +58
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 1 May 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7594-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7654-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7654-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7654-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7655-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7654-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7654-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7686-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7711-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7712-1 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: sctp: detect and prevent references to a freed transport in sendmsg sctp_sendmsg() re-uses associations and transports when possible by doing a lookup based on the socket endpoint and the message destination address, and then sctp_sendmsg_to_asoc() sets the selected transport in all the message chunks to be sent. There's a possible race condition if another thread triggers the removal of that selected transport, for instance, by explicitly unbinding an address with setsockopt(SCTP_SOCKOPT_BINDX_REM), after the chunks have been set up and before the message is sent. This can happen if the send buffer is full, during the period when the sender thread temporarily releases the socket lock in sctp_wait_for_sndbuf(). This causes the access to the transport data in sctp_outq_select_transport(), when the association outqueue is flushed, to result in a use-after-free read. This change avoids this scenario by having sctp_transport_free() signal the freeing of the transport, tagging it as "dead". In order to do this, the patch restores the "dead" bit in struct sctp_transport, which was removed in commit 47faa1e4c50e ("sctp: remove the dead field of sctp_transport"). Then, in the scenario where the sender thread has released the socket lock in sctp_wait_for_sndbuf(), the bit is checked again after re-acquiring the socket lock to detect the deletion. This is done while holding a reference to the transport to prevent it from being freed in the process. If the transport was deleted while the socket lock was relinquished, sctp_sendmsg_to_asoc() will return -EAGAIN to let userspace retry the send. The bug was found by a private syzbot instance (see the error report [1] and the C reproducer that triggers it [2]).
References
- ubuntu.com/security/CVE-2025-23142 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-23142 (opens in a new tab)
- git.kernel.org/linus/f1a69a940de58b16e8249dff26f74c8cc59b32be (opens in a new tab)
- git.kernel.org/stable/c/0f7df4899299ce4662e5f95badb9dbc57cc37fa5 (opens in a new tab)
- git.kernel.org/stable/c/2e5068b7e0ae0a54f6cfd03a2f80977da657f1ee (opens in a new tab)
- git.kernel.org/stable/c/3257386be6a7eb8a8bfc9cbfb746df4eb4fc70e8 (opens in a new tab)
- git.kernel.org/stable/c/547762250220325d350d0917a7231480e0f4142b (opens in a new tab)
- git.kernel.org/stable/c/5bc83bdf5f5b8010d1ca5a4555537e62413ab4e2 (opens in a new tab)
- git.kernel.org/stable/c/7a63f4fb0efb4e69efd990cbb740a848679ec4b0 (opens in a new tab)
- git.kernel.org/stable/c/9e7c37fadb3be1fc33073fcf10aa96d166caa697 (opens in a new tab)
- git.kernel.org/stable/c/c6fefcb71d246baaf3bacdad1af7ff50ebcfe652 (opens in a new tab)
- git.kernel.org/stable/c/f1a69a940de58b16e8249dff26f74c8cc59b32be (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7654-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7654-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7654-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7655-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7654-4 (opens in a new tab)