CVE-2026-64564: Linux kernel · Use After Free
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical · fixed in fedeb4468987bcaff85fe3061de5ae052d414740 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 1.4% chance of exploitation in 30 days – higher than 72% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in fedeb4468987bcaff85fe3061de5ae052d414740, d136b29bf91dd8e3161281b87de597b7311d9462, a63afa1f9b12d5293cbe0b77fd45dc0632533a13 +5
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 4 Aug 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.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
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.
References
- git.kernel.org/stable/c/a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293 (opens in a new tab)
- git.kernel.org/stable/c/a63afa1f9b12d5293cbe0b77fd45dc0632533a13 (opens in a new tab)
- git.kernel.org/stable/c/2b324ba3494ae958cba16a453e3e71489b4de7fc (opens in a new tab)
- git.kernel.org/stable/c/fedeb4468987bcaff85fe3061de5ae052d414740 (opens in a new tab)
- git.kernel.org/stable/c/74e8f3e7114f0e26d1b2c4c048044db9fcc27603 (opens in a new tab)
- git.kernel.org/stable/c/85aca407c560aba81b5ce9d3d6cf94c74077d19b (opens in a new tab)
- git.kernel.org/stable/c/d136b29bf91dd8e3161281b87de597b7311d9462 (opens in a new tab)
- git.kernel.org/stable/c/9b2854f86f0b56e9027d68e7a3fc909d1a9b566f (opens in a new tab)
- matrix.tencent.com/en/2026/08/06/sctphantom-CVE-2026-64564 (opens in a new tab)
- openwall.com/lists/oss-security/2026/08/06/3 (opens in a new tab)
- openwall.com/lists/oss-security/2026/08/06/4 (opens in a new tab)
- openwall.com/lists/oss-security/2026/08/06/13 (opens in a new tab)
- openwall.com/lists/oss-security/2026/08/07/1 (opens in a new tab)
- openwall.com/lists/oss-security/2026/08/07/2 (opens in a new tab)
- openwall.com/lists/oss-security/2026/08/07/8 (opens in a new tab)