iommufd: Don't overflow during division for dirty tracking
Published Dec 8, 2025
5.5
MEDIUMCVSS 3.1
EPSS 0.20%
Description
If pgshift is 63 then BITS_PER_TYPE(*bitmap->bitmap) * pgsize will overflow to 0 and this triggers divide by 0.
In this case the index should just be 0, so reorganize things to divide by shift and avoid hitting any overflows.
Affected products
-
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version
-
- Version 6.1StatusaffectedConstraints-
- Version 0StatusunaffectedConstraints<6.1
- Version 6.1.159StatusunaffectedConstraints<=6.1.*
- Version 6.12.58StatusunaffectedConstraints<=6.12.*
- Version 6.17.8StatusunaffectedConstraints<=6.17.*
- Version 6.18StatusunaffectedConstraints<=*
- Version 6.6.117StatusunaffectedConstraints<=6.6.*
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
| ||||||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
Red Hat Enterprise Linux 10
kernel
Fix deferred
Red Hat Enterprise Linux 6
kernel
Not affected
Red Hat Enterprise Linux 7
kernel
Not affected
Red Hat Enterprise Linux 7
kernel-rt
Not affected
Red Hat Enterprise Linux 8
kernel
Not affected
Red Hat Enterprise Linux 8
kernel-rt
Not affected
Red Hat Enterprise Linux 9
kernel
Fix deferred
Red Hat Enterprise Linux 9
kernel-rt
Fix deferred
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 6 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
iommufd is used for userspace IOMMU management, primarily in virtualization contexts. Triggering requires specific pgshift values of 63, which is an edge case unlikely in normal operation.
References (10)
- https://access.redhat.com/security/cve/CVE-2025-40293 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2419923 Issue Tracking
- https://git.kernel.org/stable/c/07105e61882ff4a7d58db63cc5f9e90c6c60506c
- https://git.kernel.org/stable/c/4c8a4f1d34eced168cc0b3a3dfe7b6dcc2090f69
- https://git.kernel.org/stable/c/cb30dfa75d55eced379a42fd67bd5fb7ec38555e
- https://git.kernel.org/stable/c/dbf316fc90aa954dcd5440817f4b944627ed63e0
- https://git.kernel.org/stable/c/de7f2c67ceb1941b05b04ac35458a03e93cc57b1
- https://lore.kernel.org/linux-cve-announce/2025120818-CVE-2025-40293-cfe7@gregkh/T
- https://nvd.nist.gov/vuln/detail/CVE-2025-40293
- https://www.cve.org/CVERecord?id=CVE-2025-40293
Change history (0)
No recorded changes yet.