---
cve: "CVE-2026-63830"
severity: "CRITICAL"
cvss: 9.4
epss: "35%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-07-19 12:16:56"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-08T13:57:50+02:00"
---

# CVE-2026-63830

> 9.4 CRITICAL

## Beschreibung

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

net: skmsg: preserve sg.copy across SG transforms

The sk_msg sg.copy bitmap is part of the scatterlist entry ownership
state. A set bit tells sk_msg_compute_data_pointers() not to expose the
entry through writable BPF ctx->data. This protects entries backed by
pages that are not private to the sk_msg, such as splice-backed file
page-cache pages.

Several sk_msg transform paths move, copy, split, or compact
msg->sg.data[] entries without moving the matching sg.copy bit. This can
make an externally backed entry arrive at a new slot with a clear copy
bit. A later SK_MSG verdict can then expose sg_virt(sge) as writable
ctx->data and BPF stores can modify the original page cache.

Keep sg.copy synchronized with sg.data[] whenever entries are
transferred, shifted, split, or copied into a new sk_msg. Clear the bit
when an entry is replaced by a newly allocated private page or freed.
This covers the BPF pull/push/pop helpers, sk_msg_shift_left/right(),
sk_msg_xfer(), and tls_split_open_record(), including the partial tail
entry created during TLS open-record splitting.

## CVSS-Vektor

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

| 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 | Gering | warn |

## Patch verfügbar (OSV)

- Kernel ≥ 5.10.261
- Kernel ≥ 5.15.212
- Kernel ≥ 6.1.177
- Kernel ≥ 6.6.144
- Kernel ≥ 6.12.95
- Kernel ≥ 6.18.38
- Kernel ≥ 7.1.3

## Referenzen

- <https://git.kernel.org/stable/c/f126eed589eec6f201405abbc398844042ef6d57>
- <https://git.kernel.org/stable/c/31a110642b5fb5e61940cbcfb503445ac4f28017>
- <https://git.kernel.org/stable/c/9bb86d8184b37503816150c4a6ad3c17dfdbe827>
- <https://git.kernel.org/stable/c/0eb4c16c4adb262763bda870a8ed38a1a9dec7ec>
- <https://git.kernel.org/stable/c/d22cc92bc41290e5783a72375e0843d9435f6001>
- <https://git.kernel.org/stable/c/1acdd14c0990dd1cd4b6534f00366d2e6dfce05f>
- <https://git.kernel.org/stable/c/21ed9540a8e1906dfcbc1bb82ba9b4de4fa4bd6d>
- <https://git.kernel.org/stable/c/406e8a651a7b854c41fecd5117bb282b3a6c2c6b>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-63830) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_