staging: vme_user: bound slave read/write to the kern_buf size
Summary
| CVE | CVE-2026-64449 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-25 10:17:29 UTC |
| Updated | 2026-07-25 10:17:29 UTC |
| 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 |
Risk And Classification
EPSS: 0.002150000 probability, percentile 0.119910000 (date 2026-07-25)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected f00a86d98a1ec3e99d352cda926fab767ba43b1f 65358d89dc9f1c25d9364b2b3ef0f3b47717f9ed git | Not specified |
| CNA | Linux | Linux | affected f00a86d98a1ec3e99d352cda926fab767ba43b1f adc8b9c30d716c362646edb45662aa1c641a154a git | Not specified |
| CNA | Linux | Linux | affected f00a86d98a1ec3e99d352cda926fab767ba43b1f 8eff7cd4817e14dbe3b9952cce55ef52d1d38940 git | Not specified |
| CNA | Linux | Linux | affected f00a86d98a1ec3e99d352cda926fab767ba43b1f e99f2df433c63c86c93de1e5f08f16e404388756 git | Not specified |
| CNA | Linux | Linux | affected f00a86d98a1ec3e99d352cda926fab767ba43b1f 1b495fa0d4927c88d88bf346bf311f2e26e860ed git | Not specified |
| CNA | Linux | Linux | affected f00a86d98a1ec3e99d352cda926fab767ba43b1f 9f32f38265014fac7f5dc9490fb01a638ce6e121 git | Not specified |
| CNA | Linux | Linux | affected 2.6.32 | Not specified |
| CNA | Linux | Linux | unaffected 2.6.32 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.1.178 6.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.145 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.96 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.39 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1.4 7.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2-rc3 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/9f32f38265014fac7f5dc9490fb01a638ce6e121 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/65358d89dc9f1c25d9364b2b3ef0f3b47717f9ed | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/adc8b9c30d716c362646edb45662aa1c641a154a | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/8eff7cd4817e14dbe3b9952cce55ef52d1d38940 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/e99f2df433c63c86c93de1e5f08f16e404388756 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/1b495fa0d4927c88d88bf346bf311f2e26e860ed | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.