Bug 2422797 (CVE-2025-68293)
| Summary: | CVE-2025-68293 kernel: mm/huge_memory: fix NULL pointer deference when splitting folio | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | Keywords: | Security |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A null pointer dereference flaw was found in the Linux kernel's transparent huge page (THP) splitting code. For shmem folios in swap cache or truncated folios where the mapping pointer is NULL, accessing mapping->flags causes a kernel crash. This was introduced when adding support for splitting huge pages to lower order pages.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
In the Linux kernel, the following vulnerability has been resolved: mm/huge_memory: fix NULL pointer deference when splitting folio Commit c010d47f107f ("mm: thp: split huge page to any lower order pages") introduced an early check on the folio's order via mapping->flags before proceeding with the split work. This check introduced a bug: for shmem folios in the swap cache and truncated folios, the mapping pointer can be NULL. Accessing mapping->flags in this state leads directly to a NULL pointer dereference. This commit fixes the issue by moving the check for mapping != NULL before any attempt to access mapping->flags.