Strix
64.5K

CVE-2026-89479

CRITICALCVSS 9.8/10EPSS 0.45%

Last modified

CVE-2026-89479 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: sctp: stop processing a packet once its association is deleted sctp_endpoint_bh_rcv() looks the association up only when chunk->asoc is NULL, and caches the result in chunk->asoc and chunk->transport without taking a reference. A packet that matches no association is handed to the endpoint, so a peer can bundle COOKIE ECHO, SHUTDOWN and SHUTDOWN ACK in one packet. The COOKIE ECHO creates the association, the SHUTDOWN chunk caches it, and with the outqueue empty the SHUTDOWN ACK reaches sctp_sf_do_9_2_final(), so the association and its transports are freed. The endpoint loop has no counterpart to the asoc->base.dead check in sctp_assoc_bh_rcv(). EPSS estimates a 0.45% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: stop processing a packet once its association is deleted sctp_endpoint_bh_rcv() looks the association up only when chunk->asoc is NULL, and caches the result in chunk->asoc and chunk->transport without taking a reference. A packet that matches no association is handed to the endpoint, so a peer can bundle COOKIE ECHO, SHUTDOWN and SHUTDOWN ACK in one packet. The COOKIE ECHO creates the association, the SHUTDOWN chunk caches it, and with the outqueue empty the SHUTDOWN ACK reaches sctp_sf_do_9_2_final(), so the association and its transports are freed. The endpoint loop has no counterpart to the asoc->base.dead check in sctp_assoc_bh_rcv(). The next chunk writes to last_time_heard in the freed transport and is then passed to sctp_do_sm() with the freed association. The transport is freed through RCU, so this needs the packet to come off the socket backlog, where the loop runs in task context. The endpoint loop cannot do the same check: it holds no reference on the association, so reading asoc->base.dead would itself be a use-after-free. Mark the packet for discard in the command interpreter, just before it deletes the association. That is also before sctp_inq_free() releases the chunk on the association receive path. sctp_sf_do_5_2_4_dupcook() issues SCTP_CMD_DELETE_TCB for the temporary association, while the one the packet belongs to stays alive. A restarting peer can bundle DATA behind its COOKIE ECHO, so compare against chunk->asoc and leave that case alone.

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.45%

38.0th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7d970353eeb98f46a3b9dc602850e4f6336a9889; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 09c3b193a3e8fe53e1f416e2f8e3283d2a785405; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ed85fe91a61bc0e0da6b585c07102b20f4cc65a0; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 5c0b2dbbdafc9eeeb11fffe1e46551fc3b55d8ee; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ee3f04cf566f6041aa9a0360494fd8db5ade383a; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < fa306a40e716c5abcd967475459ce1ebd56e5115; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < a713e1b3a265f180ad25a08e17be15d67a2f7149; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 47e15a8d12e366d0d261bcbc394394f44418938d
LinuxLinux2.6.12

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-89479?
In the Linux kernel, the following vulnerability has been resolved: sctp: stop processing a packet once its association is deleted sctp_endpoint_bh_rcv() looks the association up only when chunk->asoc is NULL, and caches the result in chunk->asoc and chunk->transport without taking a reference. A packet that matches no association is handed to the endpoint, so a peer can bundle COOKIE ECHO, SHUTDOWN and SHUTDOWN ACK in one packet. The COOKIE ECHO creates the association, the SHUTDOWN chunk caches it, and with the outqueue empty the SHUTDOWN ACK reaches sctp_sf_do_9_2_final(), so the association and its transports are freed. The endpoint loop has no counterpart to the asoc->base.dead check in sctp_assoc_bh_rcv(). The next chunk writes to last_time_heard in the freed transport and is then passed to sctp_do_sm() with the freed association. The transport is freed through RCU, so this needs the packet to come off the socket backlog, where the loop runs in task context. The endpoint loop cannot do the same check: it holds no reference on the association, so reading asoc->base.dead would itself be a use-after-free. Mark the packet for discard in the command interpreter, just before it deletes the association. That is also before sctp_inq_free() releases the chunk on the association receive path. sctp_sf_do_5_2_4_dupcook() issues SCTP_CMD_DELETE_TCB for the temporary association, while the one the packet belongs to stays alive. A restarting peer can bundle DATA behind its COOKIE ECHO, so compare against chunk->asoc and leave that case alone.
How severe is CVE-2026-89479?
CVE-2026-89479 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.45% probability of exploitation in the next 30 days.
How do I fix CVE-2026-89479?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →

Are you affected by CVE-2026-89479?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST