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CVE-2025-23142

sctp: detect and prevent references to a freed transport in sendmsg

HIGH 7.8

At a glance

Source
NVD
EPSS
EPSS 0.23 % · percentile 13 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

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]).

Weaknesses (CWE)

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · nvd@nist.gov (Primary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected df132eff463873e14e019a07f387b4d577d6d1f9 < 547762250220325d350d0917a7231480e0f4142b ; affected df132eff463873e14e019a07f387b4d577d6d1f9 < 3257386be6a7eb8a8bfc9cbfb746df4eb4fc70e8 ; affected df132eff463873e14e019a07f387b4d577d6d1f9 < 0f7df4899299ce4662e5f95badb9dbc57cc37fa5 ; affected df132eff463873e14e019a07f387b4d577d6d1f9 < 7a63f4fb0efb4e69efd990cbb740a848679ec4b0 ; affected df132eff463873e14e019a07f387b4d577d6d1f9 < c6fefcb71d246baaf3bacdad1af7ff50ebcfe652 ; affected df132eff463873e14e019a07f387b4d577d6d1f9 < 9e7c37fadb3be1fc33073fcf10aa96d166caa697
Linux · Linuxaffected 4.20 ; unaffected 0 < 4.20 ; unaffected 5.4.293 ≤ 5.4.* ; unaffected 5.10.237 ≤ 5.10.* ; unaffected 5.15.181 ≤ 5.15.* ; unaffected 6.1.135 ≤ 6.1.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD