---
cve: "CVE-2026-64551"
severity: "CRITICAL"
cvss: 9.1
epss: "52%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-07-27 21:17:08"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-13T00:42:54+02:00"
---

# CVE-2026-64551

> 9.1 CRITICAL

## Beschreibung

In the Linux kernel, the following vulnerability has been resolved:

sctp: validate STALE_COOKIE cause length before reading staleness

When an ERROR chunk with a STALE_COOKIE cause is received in the
COOKIE_ECHOED state, sctp_sf_do_5_2_6_stale() reads the 4-byte Measure
of Staleness that follows the cause header:

	err   = (struct sctp_errhdr *)(chunk->skb->data);
	stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));

err is the first cause in the chunk, not the STALE_COOKIE cause that
caused the dispatch, and nothing guarantees the staleness field is
present. sctp_walk_errors() only requires a cause to be as long as the
4-byte header, so for a STALE_COOKIE cause of length 4 the read runs
past the cause, and for a minimal ERROR chunk past skb->tail. The value
is echoed to the peer in the Cookie Preservative of the reply INIT,
leaking uninitialized memory.

sctp_sf_cookie_echoed_err() already walks to the STALE_COOKIE cause, so
check its length there and pass it to sctp_sf_do_5_2_6_stale(), which
reads that cause instead of the first one. A STALE_COOKIE cause too
short to hold the staleness field is discarded.

The read is reachable by any peer that can drive an association into
COOKIE_ECHOED, including an unprivileged process using a raw SCTP socket
in a user and network namespace.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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 | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 5.10.261
- Kernel ≥ 5.15.212
- Kernel ≥ 6.1.178
- Kernel ≥ 6.6.145
- Kernel ≥ 6.12.97
- Kernel ≥ 6.18.40
- Kernel ≥ 7.1.5

## Referenzen

- <https://git.kernel.org/stable/c/6022da37786701df1fc5dd946a6dcba59d5473b1>
- <https://git.kernel.org/stable/c/861f884f5471632c731cbbd612a1c072e391a624>
- <https://git.kernel.org/stable/c/588706ebaf8cdb4a4161602949eba365514b1db1>
- <https://git.kernel.org/stable/c/a257b41ddfe9e327b26581ad2777f04b23ac73f5>
- <https://git.kernel.org/stable/c/08a8f2d13f703924316e9aeac863a88ef50990c7>
- <https://git.kernel.org/stable/c/ebe0a55d954fa8da383b6192edb8f763dcb002d5>
- <https://git.kernel.org/stable/c/bbd6b2ea966cf57b6ae095cf5a8dbc993cd197a0>
- <https://git.kernel.org/stable/c/1cd23ca80784223fa2204e16203f754da4e821f8>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-64551) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_