What is CVE-2026-64323?

CVE-2026-64323 is a unscored severity Linux kernel vulnerability, affecting Linux kernel versions from 2.6.26 onward and patched in 5.10.261, 5.15.212, 6.1.178 and others. CVE-2026-64323 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-64323?

CVE-2026-64323 has a CVSS score of pending NVD analysis out of 10, rated awaiting scoring severity.

Is there a patch available for CVE-2026-64323?

Yes, CVE-2026-64323 has been patched. Fixed versions include 5.10.261, 5.15.212, 6.1.178 and others. If you are running Linux kernel 2.6.26 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-64323 actively exploited?

CVE-2026-64323 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-64323

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.

Package Linux Kernel

Published 2026-07-25

Last modified 2026-07-25

Patch available

Yes

Affected versions

Linux kernel versions 2.6.26 and later are affected. 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-rc1 and their respective stable series.

Affected from

≥ 2.6.26

Fixed in

✓ 5.10.261 5.10.x ✓ 5.15.212 5.15.x ✓ 6.1.178 6.1.x ✓ 6.6.145 6.6.x ✓ 6.12.96 6.12.x ✓ 6.18.39 6.18.x ✓ 7.1.4 7.1.x ✓ 7.2-rc1

References

8 total

Showing 5 of 8 references View all on NVD

Frequently asked questions

What is CVE-2026-64323?

CVE-2026-64323 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 2.6.26 onward and has been patched in 5.10.261, 5.15.212, 6.1.178 and others. CVE-2026-64323 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
Is there a patch available for CVE-2026-64323?

Yes. CVE-2026-64323 has been patched. Fixed versions include 5.10.261, 5.15.212, 6.1.178 and others. If you are running Linux kernel 2.6.26 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-64323 actively exploited?

No. CVE-2026-64323 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.