{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89477","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.711Z","datePublished":"2026-09-11T19:43:33.851Z","dateUpdated":"2026-09-14T12:00:13.880Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-14T12:00:13.880Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix NULL deref on untransmitted RECONF completion\n\nsctp_process_strreset_outreq(), sctp_process_strreset_addstrm_out() and\nsctp_process_strreset_resp() complete a pending stream reconfiguration\nrequest by stopping the reconf timer on the transport it was sent on:\n\n\tt = asoc->strreset_chunk->transport;\n\tif (timer_delete(&t->reconf_timer))\n\t\tsctp_transport_put(t);\n\nchunk->transport is assigned by __sctp_packet_append_chunk() when the\nchunk is appended to an outbound packet, and sctp_outq_flush_ctrl() arms\nthe reconf timer at that same point. A request already published in\nasoc->strreset_chunk but not yet transmitted has neither, so completing\nit dereferences NULL.\n\nTwo ways to get there. sctp_send_asconf_del_ip() sets\nasoc->src_out_of_asoc_ok without sending anything when the address being\nremoved is the association's last one, and sctp_outq_flush_ctrl() then\nleaves every non-ASCONF control chunk queued; as only\nsctp_process_asconf_ack() clears that flag, it persists. An unprivileged\nprocess that removes such an address and then asks for a stream reset\npanics the kernel from softirq. A peer needs neither ASCONF nor local\nhelp: sctp_cmd_interpreter() uncorks the outqueue only once the whole\npacket has been processed, so a reply built while walking a RECONF chunk\nstays untransmitted for the rest of that walk, and one RECONF chunk\ncarrying [Incoming SSN Reset Request, Outgoing SSN Reset Request,\nResponse] -- or two RECONF chunks in one packet -- reaches the same\ndereference.\n\n  KASAN: null-ptr-deref in range [0x00000000000001e8-0x00000000000001ef]\n  RIP: 0010:timer_delete+0x67/0x110\n  Call Trace:\n   <IRQ>\n   sctp_process_strreset_addstrm_out (net/sctp/stream.c:832)\n   sctp_sf_do_reconf (net/sctp/sm_statefuns.c:4212)\n   sctp_do_sm (net/sctp/sm_sideeffect.c:1172)\n   sctp_assoc_bh_rcv (net/sctp/associola.c:1044)\n   sctp_rcv (net/sctp/input.c:243)\n   ip_local_deliver (net/ipv4/ip_input.c:262)\n   process_backlog (net/core/dev.c:6680)\n   </IRQ>\n\nA response can only acknowledge a request that was actually sent, so do\nnot match asoc->strreset_chunk while chunk->transport is NULL. Guarding\nthe lookup covers all three completion sites."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - A remote SCTP peer reaches the bug via sctp_rcv() -> sctp_assoc_bh_rcv() -> sctp_sf_do_reconf() on an established association; one RECONF carrying Incoming/Outgoing SSN Reset plus Response, or two bundled RECONF chunks, completes an untransmitted strreset_chunk. This is internet-facing SCTP (telecom/Diameter), not a local-only syscall.\nAC:L - The attacker fully controls the packet: sctp_cmd_interpreter() keeps the outqueue corked until the whole packet is processed, so the generated RECONF reply stays untransmitted and the follow-on parameter/chunk deterministically NULL-dereferences. request_seq is the peer's initial TSN from INIT/INIT-ACK; no race or uninfluenceable memory layout is required.\nPR:N - Triggering requires only a network-reachable established SCTP association; the attacker needs no local account, capabilities, or namespaces on the victim. RECONF is processed in ESTABLISHED without SCTP-AUTH by default (empty auth chunk list), so no extra credentials beyond being the SCTP peer.\nUI:N - Exploitation is driven entirely by inbound SCTP packets processed automatically in softirq on a listening or already-associated endpoint; no victim user action such as opening a file or mounting a filesystem is required.\nS:U - Impact is a kernel NULL dereference and oops in the host SCTP stack, remaining in the same kernel security authority; it is not a VM/guest-to-host escape, IOMMU bypass, or other cross-boundary breakout.\nC:N - The defect is a pure NULL pointer dereference of strreset_chunk->transport in timer_delete() (KASAN range around offset 0x1e8). No out-of-bounds read, UAF object reuse, or other disclosure primitive is involved.\nI:N - Only a NULL transport pointer is loaded and passed to timer_delete(); there is no write, type confusion, or memory corruption that could hijack control flow or modify kernel state beyond the crash.\nA:H - timer_delete() on the NULL transport oopses/panics the kernel from SCTP receive softirq (documented KASAN null-ptr-deref in sctp_process_strreset_*), which is a full availability loss and can be repeated at will by the peer."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sctp/stream.c"],"versions":[{"version":"81054476453640159149cb6704e834893e16736b","lessThan":"79ff751311e80fa0370007e46a79a6d601685e75","status":"affected","versionType":"git"},{"version":"81054476453640159149cb6704e834893e16736b","lessThan":"53141db979687eae7dc6d29414cefc77034f967e","status":"affected","versionType":"git"},{"version":"81054476453640159149cb6704e834893e16736b","lessThan":"68891125af5a5dfbca728809a16637a869bbe0df","status":"affected","versionType":"git"},{"version":"81054476453640159149cb6704e834893e16736b","lessThan":"b2d6d873b4dfb5b84194061c4b40a1cd85b92ca4","status":"affected","versionType":"git"},{"version":"81054476453640159149cb6704e834893e16736b","lessThan":"77ea60f2d24002c308f224db44a4542c466489af","status":"affected","versionType":"git"},{"version":"81054476453640159149cb6704e834893e16736b","lessThan":"25419f516ea84b1e7d3d55aae5215ac86ece0c66","status":"affected","versionType":"git"},{"version":"81054476453640159149cb6704e834893e16736b","lessThan":"0ee697defc0594f1da810ed75d9d643fb46f5318","status":"affected","versionType":"git"},{"version":"81054476453640159149cb6704e834893e16736b","lessThan":"2db9bfa3e27bdea15e05ea70b56bad3d21e570ec","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sctp/stream.c"],"versions":[{"version":"4.11","status":"affected"},{"version":"0","lessThan":"4.11","status":"unaffected","versionType":"semver"},{"version":"5.10.270","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.221","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.188","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.157","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.109","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.50","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.4","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"5.10.270"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.11","versionEndExcluding":"7.3-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/79ff751311e80fa0370007e46a79a6d601685e75"},{"url":"https://git.kernel.org/stable/c/53141db979687eae7dc6d29414cefc77034f967e"},{"url":"https://git.kernel.org/stable/c/68891125af5a5dfbca728809a16637a869bbe0df"},{"url":"https://git.kernel.org/stable/c/b2d6d873b4dfb5b84194061c4b40a1cd85b92ca4"},{"url":"https://git.kernel.org/stable/c/77ea60f2d24002c308f224db44a4542c466489af"},{"url":"https://git.kernel.org/stable/c/25419f516ea84b1e7d3d55aae5215ac86ece0c66"},{"url":"https://git.kernel.org/stable/c/0ee697defc0594f1da810ed75d9d643fb46f5318"},{"url":"https://git.kernel.org/stable/c/2db9bfa3e27bdea15e05ea70b56bad3d21e570ec"}],"title":"sctp: fix NULL deref on untransmitted RECONF completion","x_generator":{"engine":"bippy-1.2.0"}}}}