CVE-2026-89479: Linux kernel · sctp: stop processing a packet once its association is deleted
Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2026
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.
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.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89479 (opens in a new tab)
- git.kernel.org/stable/c/09c3b193a3e8fe53e1f416e2f8e3283d2a785405 (opens in a new tab)
- git.kernel.org/stable/c/47e15a8d12e366d0d261bcbc394394f44418938d (opens in a new tab)
- git.kernel.org/stable/c/5c0b2dbbdafc9eeeb11fffe1e46551fc3b55d8ee (opens in a new tab)
- git.kernel.org/stable/c/7d970353eeb98f46a3b9dc602850e4f6336a9889 (opens in a new tab)
- git.kernel.org/stable/c/a713e1b3a265f180ad25a08e17be15d67a2f7149 (opens in a new tab)
- git.kernel.org/stable/c/ed85fe91a61bc0e0da6b585c07102b20f4cc65a0 (opens in a new tab)
- git.kernel.org/stable/c/ee3f04cf566f6041aa9a0360494fd8db5ade383a (opens in a new tab)
- git.kernel.org/stable/c/fa306a40e716c5abcd967475459ce1ebd56e5115 (opens in a new tab)