# CVE-2026-64564 — Linux > As of 2026-08-19, CVE-2026-64564 is a CRITICAL-severity vulnerability in Linux, CVSS v3.1 9.8, EPSS 1.4% (71.8th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-64564, most recently “SCTPhantom (CVE-2026-64564): 18-Year-Old Use-After-Free in Linux Kernel SCTP ASCONF Handling Enables Local Privilege Escalation”. **Last updated:** 2026-08-19 ## What is CVE-2026-64564? In the Linux kernel, the following vulnerability has been resolved: sctp: don't free the ASCONF's own transport in DEL-IP processing sctp_process_asconf() caches the transport the ASCONF chunk is processed against in asconf->transport (== chunk->transport, set once in sctp_rcv()). For an ASCONF located through its Address Parameter by __sctp_rcv_asconf_lookup(), that cached transport corresponds to the Address Parameter, which need not be the packet's source address. sctp_process_asconf_param() rejects a DEL-IP for the packet source address (ADDIP D8, SCTP_ERROR_DEL_SRC_IP), but nothing protects asconf->transport. A single ASCONF can therefore carry, in order: [Address Parameter L] [DEL-IP L] [DEL-IP 0.0.0.0] where L differs from the source. The DEL-IP for L passes the D8 check and calls sctp_assoc_rm_peer() on the transport that asconf->transport still points at, freeing it (RCU-deferred). The following wildcard DEL-IP then reuses the now-dangling asconf->transport in sctp_assoc_set_primary() and sctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed transport (->ipaddr, ->state) and plants the dangling pointer into asoc->peer.primary_path / active_path, and del_nonprimary_peers(), keeping only the pointer that is no longer on the list, removes every real transport, leaving the association with a transport_count of 0 and primary_path/active_path pointing at freed memory. Reject a DEL-IP that targets the transport the ASCONF is being processed against, mirroring the existing source-address guard, so the wildcard branch can never reuse a freed transport. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 85 days ago. ## Severity and exploitation probability - **CVSS v3.1 base score:** 9.8 — CRITICAL (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`) - **EPSS (FIRST):** 1.4% probability of exploitation in the next 30 days, higher than 71.8% of all scored CVEs - **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog - **Threadlinqs priority:** 9.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability - **Published:** 2026-08-04, last modified 2026-08-19 ## Is CVE-2026-64564 being exploited? Weaponised exploit code for CVE-2026-64564 is publicly available. 5 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 44 in the Threadlinqs vulnerability feed. - [ethanolgolf/CVE-2026-64564](https://github.com/ethanolgolf/CVE-2026-64564) (github) - [HackSpeak/CVE-2026-64564](https://github.com/HackSpeak/CVE-2026-64564) (github) - [0xdeadroot/SCTPhantom-CVE-2026-64564](https://github.com/0xdeadroot/SCTPhantom-CVE-2026-64564) (github) - [suominen/sctphantom](https://github.com/suominen/sctphantom) (github) - [yandex-cloud-examples/yc-mk8s-sctphantom-mitigation](https://github.com/yandex-cloud-examples/yc-mk8s-sctphantom-mitigation) (github) ## Affected products and versions - [Linux](https://intel.threadlinqs.com/vendors/linux): Linux ## How to fix CVE-2026-64564 No vendor patch reference has been recorded for CVE-2026-64564 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise. ## Threat activity tracking CVE-2026-64564 1 tracked threat in the Threadlinqs corpus references CVE-2026-64564, either in the campaign’s CVE list or as an indicator on the campaign record. - [SCTPhantom (CVE-2026-64564): 18-Year-Old Use-After-Free in Linux Kernel SCTP ASCONF Handling Enables Local Privilege Escalation](https://intel.threadlinqs.com/threat/TL-2026-1949) — HIGH · 2026-08-09 ## Sources Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-10-10. **Other references** - [git.kernel.org](https://git.kernel.org/stable/c/a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293) - [git.kernel.org (a63afa1f9b12d5293cbe0b77fd45dc0632533a13)](https://git.kernel.org/stable/c/a63afa1f9b12d5293cbe0b77fd45dc0632533a13) - [git.kernel.org (2b324ba3494ae958cba16a453e3e71489b4de7fc)](https://git.kernel.org/stable/c/2b324ba3494ae958cba16a453e3e71489b4de7fc) - [git.kernel.org (fedeb4468987bcaff85fe3061de5ae052d414740)](https://git.kernel.org/stable/c/fedeb4468987bcaff85fe3061de5ae052d414740) - [git.kernel.org (74e8f3e7114f0e26d1b2c4c048044db9fcc27603)](https://git.kernel.org/stable/c/74e8f3e7114f0e26d1b2c4c048044db9fcc27603) _Showing 5 of 9 recorded references._ Canonical: https://intel.threadlinqs.com/cve/CVE-2026-64564 Full detection coverage and IOCs for threats exploiting CVE-2026-64564 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp