---
cve: "CVE-2026-74588"
severity: "CRITICAL"
cvss: 9.8
epss: "76.4%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-08-22 16:16:30"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-05T16:47:21+02:00"
---

# CVE-2026-74588

> 9.8 CRITICAL

## Beschreibung

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

sctp: keep chunk->transport in step with the list it is queued on

__sctp_outq_flush_rtx() moves a gap-acked chunk onto another transport's
transmitted list without updating chunk->transport:

	if (chunk->tsn_gap_acked) {
		list_move_tail(&chunk->transmitted_list,
			       &transport->transmitted);
		continue;
	}

The chunk then sits on a live transport's list while chunk->transport still
names a different one.  If that transport is removed - sctp_assoc_rm_peer()
from an ASCONF Delete-IP - sctp_transport_free() RCU-frees it and the chunk
is left with a dangling pointer.  sctp_assoc_rm_peer() scrubs
peer->transmitted and asoc->outqueue.out_chunk_list, but the chunk is on
neither.

The pointer is not followed while tsn_gap_acked is set.  A SACK that
reneges on the TSN clears the flag, and the next SACK reaches

	tchunk->transport->flight_size -= sctp_data_size(tchunk);

inside the freed transport.  KASAN reports a slab-use-after-free read in
sctp_check_transmitted(), freed from sctp_assoc_rm_peer().  Both the
removal and the SACKs come from the association peer.

Set chunk->transport at the move.  The ordinary resend path needs nothing:
it reaches its list_move_tail() only after sctp_packet_append_chunk()
returned SCTP_XMIT_OK, and __sctp_packet_append_chunk() has rebound the
chunk by then.

Discovered by XBOW, triaged by Baul Lee

## 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 ≥ 6.6.152
- Kernel ≥ 6.12.104
- Kernel ≥ 6.18.45
- Kernel ≥ 7.1.9

## Referenzen

- <https://git.kernel.org/stable/c/1adf929121e13e0b19200bb9fef715b918d483fe>
- <https://git.kernel.org/stable/c/2b3b5eec8b2c30ee237e3c31a6a38de9c39d804d>
- <https://git.kernel.org/stable/c/5ccf35ef0ed6059cdf8b1f4606a6584d5b67166b>
- <https://git.kernel.org/stable/c/6575fb17230814b48b471727c8410c0aadff9274>
- <https://git.kernel.org/stable/c/6b9e2ea2057113f3393990ba646d2d97c719a80d>
- <https://git.kernel.org/stable/c/874a7c2b5e184f06134fdfde27e9ce9271bafe58>
- <https://git.kernel.org/stable/c/9f2cf069a9a72a2d6b97ca8b4c70e714aac99749>
- <https://git.kernel.org/stable/c/e2e7c1de0e226ca1b7fea2de57a6c9bca408709b>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-74588) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_