{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-98548 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-98548 is a critical use after free vulnerability in Linux, published on 18 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-98548 and fix it if it is affected.\n\nWhat it is: CVE-2026-98548 is a critical use after free vulnerability in Linux, published on 18 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-98548 in the wild and no public exploit code.\n\nAffected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-98548/ (Markdown: https://insights.sbomify.com/CVE-2026-98548/index.md)","id":"CVE-2026-98548","markdown":"https://insights.sbomify.com/CVE-2026-98548/index.md","name":"CVE-2026-98548","record":{"aliases":["AZL-108680","BELL-CVE-2026-98548","DEBIAN-CVE-2026-98548","GHSA-3mq3-vc9v-9wmc","UBUNTU-CVE-2026-98548"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","privilege_escalation"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel SCTP","requires_auth":"none","summary":"A use-after-free in the Linux kernel SCTP implementation allows remote attackers to execute arbitrary code or escalate privileges via crafted packets.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":9.8,"severity":"critical","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: discard the rest of the packet on a stale-cookie error\n\nWhen an association is in COOKIE-ECHOED state and the peer sends a\nbundled [ERROR(Stale Cookie)][DATA] packet from one of its non-primary\naddresses, processing the ERROR chunk takes the non-fatal stale-cookie\nretry path sctp_sf_do_5_2_6_stale(), which queues\nSCTP_CMD_DEL_NON_PRIMARY while keeping the association alive.\nsctp_cmd_del_non_primary() removes every non-primary transport -\nincluding the very transport this packet arrived on, which is still\nreferenced by the receive lookup and shared by all chunks of the\npacket via chunk-\u003etransport.\n\nsctp_assoc_rm_peer() does redirect asoc-\u003epeer.last_data_from away from\nthe removed transport, but right afterwards the bundled DATA chunk\nmakes sctp_assoc_bh_rcv() re-register\nasoc-\u003epeer.last_data_from = chunk-\u003etransport unconditionally, undoing\nthe redirection with the just-removed transport.\n\nOnce the packet is done, the receive reference is dropped and the\ntransport is RCU-freed, while the surviving association keeps the\ndangling last_data_from.  A later FWD-TSN (or the delayed SACK timer)\nmakes sctp_gen_sack() dereference it (-\u003eparam_flags and friends), and\nsctp_make_sack()/sctp_outq_select_transport() may write to the freed\nobject and link it into the live transport list.  This is a\nuse-after-free triggerable by any malicious SCTP peer (or a local\nunprivileged user acting as one) with no capabilities required:\n\n  BUG: KASAN: slab-use-after-free in sctp_do_sm+0x498a/0x5660\n  Read of size 4 at addr ffff88800e1e356c by task poc/115\n  Call Trace: sctp_do_sm \u003c- sctp_assoc_bh_rcv \u003c- sctp_inq_push \u003c-\n              sctp_rcv \u003c- ip_protocol_deliver_rcu \u003c- ip_rcv\n  Allocated: sctp_transport_new \u003c- sctp_assoc_add_peer \u003c-\n             sctp_process_init (INIT-ACK processing)\n  Freed: kfree \u003c- sctp_transport_destroy_rcu \u003c- rcu_core\n         (call_rcu queued by sctp_transport_put at end of sctp_rcv)\n  The buggy address is located 364 bytes inside of freed 1024-byte\n  region [ffff88800e1e3400, ffff88800e1e3800), cache kmalloc-1k\n\nNote that commit 03a9d10ecf71 (\"sctp: drop a chunk if its transport\nwas removed\") only covers the window between the receive lookup and\nthe chunk processing (e.g. an ASCONF DEL-IP racing the socket backlog);\nhere the transport is removed *while* the packet is being processed,\nby an earlier chunk of the same packet, so the drop in sctp_inq_push()\ndoes not reach this path.  Verified with the bundled [ERROR(Stale\nCookie)][DATA] + FWD-TSN reproducer: the KASAN report above still\nfires with that commit applied, and is gone with this patch on top.\n\nFix it by discarding the rest of the packet on this path, as suggested\nby Xin.  After the stale-cookie ERROR has sent the association back to\nCOOKIE-WAIT and removed the non-primary transports, the remaining\nchunks of the packet can only run against the restarted handshake\nwhile referencing the removed arrival transport through\nchunk-\u003etransport: besides the last_data_from registration above,\nsctp_cmd_setup_t2() and the sctp_make_*() reply builders would also\ncopy that pointer into association-lifetime state that\nsctp_assoc_rm_peer() has already sanitized.  Let the peer retransmit\nthem, in line with what sctp_inq_push() does for chunks whose\ntransport was removed before processing.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"sctp: discard the rest of the packet on a stale-cookie error","id":"CVE-2026-98548","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"use_after_free","year":"2026"},"n_packages":0,"n_references":8,"next":{"headline":"tcp: prevent collapsing skbs across boundary in rtx queue","id":"CVE-2026-98549"},"packages":[],"prev":{"headline":"af_packet: fix integer overflow in prb_calc_retire_blk_tmo()","id":"CVE-2026-98547"},"products":["Linux"],"published":"2026-10-18","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-24","vendors":["Linux"]},"summary":"A use-after-free in the Linux kernel SCTP implementation allows remote attackers to execute arbitrary code or escalate privileges via crafted packets.","url":"https://insights.sbomify.com/CVE-2026-98548/"}