CVE-2026-64564 — sctp: don't free the ASCONF's own transport in DEL-IP processing
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (critical)+10
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
≥ 42e30bf3463cd37d73839376662cb79b4d5c416c and < a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293≥ 42e30bf3463cd37d73839376662cb79b4d5c416c and < a63afa1f9b12d5293cbe0b77fd45dc0632533a13≥ 42e30bf3463cd37d73839376662cb79b4d5c416c and < 2b324ba3494ae958cba16a453e3e71489b4de7fc≥ 42e30bf3463cd37d73839376662cb79b4d5c416c and < fedeb4468987bcaff85fe3061de5ae052d414740≥ 42e30bf3463cd37d73839376662cb79b4d5c416c and < 74e8f3e7114f0e26d1b2c4c048044db9fcc27603≥ 42e30bf3463cd37d73839376662cb79b4d5c416c and < 85aca407c560aba81b5ce9d3d6cf94c74077d19b≥ 42e30bf3463cd37d73839376662cb79b4d5c416c and < d136b29bf91dd8e3161281b87de597b7311d9462≥ 42e30bf3463cd37d73839376662cb79b4d5c416c and < 9b2854f86f0b56e9027d68e7a3fc909d1a9b566f and 1 moreversion 2.6.25 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 9.8 | CVSS 3.1 | Critical | 3.9 | 5.9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database |
| 9.8 | CVSS 3.1 | Critical | — | — | Linux via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- Record published
- CVSS changed · 9.8
- Source status changed · → Received
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
15 on the record
- git.kernel.org/stable/c/a63afa1f9b12d5293cbe0b77fd45dc0632533a13
- git.kernel.org/stable/c/2b324ba3494ae958cba16a453e3e71489b4de7fc
- www.openwall.com/lists/oss-security/2026/08/06/13
- git.kernel.org/stable/c/74e8f3e7114f0e26d1b2c4c048044db9fcc27603
- git.kernel.org/stable/c/a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293
- git.kernel.org/stable/c/85aca407c560aba81b5ce9d3d6cf94c74077d19b
- www.openwall.com/lists/oss-security/2026/08/07/8
- git.kernel.org/stable/c/d136b29bf91dd8e3161281b87de597b7311d9462
- www.openwall.com/lists/oss-security/2026/08/07/2
- git.kernel.org/stable/c/9b2854f86f0b56e9027d68e7a3fc909d1a9b566f
- matrix.tencent.com/en/2026/08/06/sctphantom-CVE-2026-64564
- www.openwall.com/lists/oss-security/2026/08/06/4
- git.kernel.org/stable/c/fedeb4468987bcaff85fe3061de5ae052d414740
- www.openwall.com/lists/oss-security/2026/08/07/1
- www.openwall.com/lists/oss-security/2026/08/06/3
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 11h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 11h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-64564 is "sctp: don't free the ASCONF's own transport in DEL-IP processing", rated Critical. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.8 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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