udf: validate VAT header length against the VAT inode size
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · High
- Fix status
- Partial Red Hat: 5 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.26 and later | 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.26 and later Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 2.6.26 to before 5.10.261; 5.11 to before 5.15.212; 5.16 to before 6.1.178; 6.2 to before 6.6.145; 6.7 to before 6.12.96; 6.13 to before 6.18.39; 6.19 to before 7.1.4 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 2.6.26 to before 5.10.261; 5.11 to before 5.15.212; 5.16 to before 6.1.178; 6.2 to before 6.6.145; 6.7 to before 6.12.96; 6.13 to before 6.18.39; 6.19 to before 7.1.4 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-64323
- 2026-10-03 Alias added: GHSA-rjqr-92w7-gfg4
- 2026-10-13 Affected versions changed · Red Hat
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-20 Weakness changed · CISA ADP
- 2026-10-27 CVSS score changed · Red Hat
References
Patch 8
- 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
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- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2026-64323 · CVE Program
- CVE-2026-64323 · NVD
- FIRST EPSS
- GHSA-rjqr-92w7-gfg4 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-64323 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences