# CVE-2026-64449: linux: In the Linux kernel, the following vulnerability has been resolved:  staging: vme_user: bound slave read/write to the...

CVE-2026-64449 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-64449, released July 26, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-64449
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0014
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 25, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  staging: vme_user: bound slave read/write to the kern_buf size  The SLAVE-path helpers buffer_to_user() and buffer_from_user() copy 'count' bytes into/out of the fixed-size kern_buf (size_buf == PCI_BUF_SIZE == 0x20000, 128 KiB) using *ppos as the offset, without bounding *ppos + count against size_buf.  vme_user_write()/vme_user_read() only clamp count to the VME window size (image_size = vme_get_size(resource)), which VME_SET_SLAVE sets from the user-supplied slave.size -- validated against the VME address space (up to VME_A32_MAX = 4 GiB), not against PCI_BUF_SIZE.  When the window exceeds 128 KiB, a write()/read() copies past the kern_buf allocation.  Clamp count against size_buf in both helpers, with an early return when *ppos is already at/after the buffer end.  *ppos is >= 0 here (the caller rejects negative offsets), so size_buf - *ppos cannot wrap.  This mirrors the existing clamp in the MASTER-path helpers resource_to_user() / resource_from_user(), and matches the read()/write() convention of a short transfer at end-of-buffer.  Found by static analysis (CodeQL taint tracking + CBMC bounded model checking) and confirmed dynamically under KASAN with the vme_fake bridge:    BUG: KASAN: slab-out-of-bounds in _copy_from_user+0x2d/0x80   Write of size 262144 at addr ffff888004100000 by task trigger/68     _copy_from_user+0x2d/0x80     vme_user_write+0x13e/0x240 [vme_user]     vfs_write+0x1b8/0x7a0     ksys_write+0xb8/0x150

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.180-1 | [DEBIAN-CVE-2026-64449](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64449.md) | Jul 26, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.96-1 | [DEBIAN-CVE-2026-64449](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64449.md) | Jul 26, 2026 |
| Linux | linux Debian 14 | 7.1.4-1 | [DEBIAN-CVE-2026-64449](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64449.md) | Jul 26, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.100-1~deb12u1 | [DEBIAN-CVE-2026-64449](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64449.md) | Jul 26, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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