---
cve: "CVE-2026-64564"
severity: "CRITICAL"
cvss: 9.8
epss: "50%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-08-04 07:16:31"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-09T12:25:41+02:00"
---

# CVE-2026-64564

> 9.8 CRITICAL

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 5.10.265
- Kernel ≥ 5.15.216
- Kernel ≥ 6.1.183
- Kernel ≥ 6.6.148
- Kernel ≥ 6.12.101
- Kernel ≥ 6.18.42
- Kernel ≥ 7.1.6

## Referenzen

- <https://git.kernel.org/stable/c/a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293>
- <https://git.kernel.org/stable/c/a63afa1f9b12d5293cbe0b77fd45dc0632533a13>
- <https://git.kernel.org/stable/c/2b324ba3494ae958cba16a453e3e71489b4de7fc>
- <https://git.kernel.org/stable/c/fedeb4468987bcaff85fe3061de5ae052d414740>
- <https://git.kernel.org/stable/c/74e8f3e7114f0e26d1b2c4c048044db9fcc27603>
- <https://git.kernel.org/stable/c/85aca407c560aba81b5ce9d3d6cf94c74077d19b>
- <https://git.kernel.org/stable/c/d136b29bf91dd8e3161281b87de597b7311d9462>
- <https://git.kernel.org/stable/c/9b2854f86f0b56e9027d68e7a3fc909d1a9b566f>
- <https://matrix.tencent.com/en/2026/08/06/sctphantom-CVE-2026-64564>
- <http://www.openwall.com/lists/oss-security/2026/08/06/13>
- <http://www.openwall.com/lists/oss-security/2026/08/06/3>
- <http://www.openwall.com/lists/oss-security/2026/08/06/4>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-64564) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_