---
cve: "CVE-2026-64323"
severity: "HIGH"
cvss: 7.1
epss: "16%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-07-25 10:17:13"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-10T07:48:15+02:00"
---

# CVE-2026-64323

> 7.1 HIGH

## Beschreibung

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

udf: validate VAT header length against the VAT inode size

udf_load_vat() takes the virtual partition's start offset straight from
the on-disk VAT 2.0 header without checking it against the VAT inode
size:

	map->s_type_specific.s_virtual.s_start_offset =
		le16_to_cpu(vat20->lengthHeader);
	map->s_type_specific.s_virtual.s_num_entries =
		(sbi->s_vat_inode->i_size -
			map->s_type_specific.s_virtual.s_start_offset) >> 2;

lengthHeader is a fully attacker-controlled 16-bit value.  If it exceeds
the VAT inode size, the s_num_entries subtraction underflows to a huge
count, which defeats the "block > s_num_entries" bound in
udf_get_pblock_virt15(); and on the ICB-inline path that function reads

	((__le32 *)(iinfo->i_data + s_start_offset))[block]

so a large s_start_offset indexes past the inode's in-ICB data.  Mounting
a crafted UDF image with a virtual (VAT) partition then triggers an
out-of-bounds read.

Reject a VAT whose header length does not leave room for at least one
entry within the VAT inode.

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| 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 ≥ 6.12.96
- Kernel ≥ 6.18.39
- Kernel ≥ 7.1.4

## Referenzen

- <https://git.kernel.org/stable/c/0ad2d09a8d66fa8dc6f9b70d660b5fb4478ea934>
- <https://git.kernel.org/stable/c/883962731420ec271ed8c1cd76524f4b17faa982>
- <https://git.kernel.org/stable/c/2900e02a0dd4fc30ac9840e7ce4ca0b041ab0d63>
- <https://git.kernel.org/stable/c/bb0d384c1f42a5b7ace0bd88fee80b9bb1d49acb>
- <https://git.kernel.org/stable/c/55287a3555ff0515b3aff181d2c08c0462a41709>
- <https://git.kernel.org/stable/c/e610fb113cdfa8bf4247c9bf4f2337b81ad4ddad>
- <https://git.kernel.org/stable/c/74580fdf022909e184223cacc364feb826982d96>
- <https://git.kernel.org/stable/c/d8202786b3d75125c84ebc4de6d946f92fde0ee8>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-64323) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_