Описание
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]).
A flaw was found in the Linux kernel's SCTP implementation. This vulnerability allows a use-after-free read via a race condition during SCTP message sending.
Отчет
This is a MODERATE impact use-after-free flaw,found in the Linux kernel's Stream Control Transmission Protocol (SCTP) implementation. This race condition occurs during message sending,the kernel function sctp_sendmsg() sends SCTP messages by selecting a transport (network path) and associating it with message chunks. If another thread removes that transport (e.g., by unbinding an address using setsockopt(SCTP_SOCKOPT_BINDX_REM)) after the transport has been selected but before the message is sent, the code can end up accessing a transport that has been freed from memory, leading to a use after free. Red Hat Enterprise Linux 9 is affected. Red Hat Enterprise Linux 10 and Red Hat In-Vehicle OS are not affected as the vulnerable code is not present.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use anhd deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Not affected | ||
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope | ||
| Red Hat Enterprise Linux 8 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Out of support scope | ||
| Red Hat Enterprise Linux 9 | kernel | Affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | kernel | Fixed | RHSA-2026:0576 | 14.01.2026 |
| Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | kernel-rt | Fixed | RHSA-2026:0537 | 14.01.2026 |
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Дополнительная информация
Статус:
7.5 High
CVSS3
Связанные уязвимости
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_tran...
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_tr
sctp: detect and prevent references to a freed transport in sendmsg
In the Linux kernel, the following vulnerability has been resolved: s ...
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...
7.5 High
CVSS3