PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-53154 Linux CVE debrief

CVE-2026-53154 is a vulnerability in the Linux kernel that affects the hugetlb folio copy paths. The vulnerability arises from a missing restore_reserve_on_error() call before folio_put() on error paths in hugetlb_mfill_atomic_pte() and copy_hugetlb_page_range(). This omission leads to a reservation leak in the VMA's reserve map, potentially causing a SIGBUS error at a previously reserved address under hugetlb pool pressure. The vulnerability was introduced due to changes in copy_user_large_folio(), which now returns an integer and can fail, for example, with -EHWPOISON on a hwpoisoned source page.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-25
Original CVE updated
2026-06-30
Advisory published
2026-06-25
Advisory updated
2026-06-30

Who should care

System administrators and security teams responsible for Linux kernel-based systems should be aware of this vulnerability. Given the nature of the vulnerability, which involves hugetlb folio copy paths, systems utilizing huge pages, such as those configured for high-performance computing or specific memory-intensive workloads, are most at risk. Linux distributions and vendors should prioritize patching to mitigate potential exploitation.

Technical summary

The vulnerability is located in the Linux kernel's mm/hugetlb.c file, specifically affecting the hugetlb_mfill_atomic_pte() resubmission path (UFFDIO_COPY) and the copy_hugetlb_page_range() fork-time CoW path. When copy_user_large_folio() fails, for instance due to encountering a hwpoisoned source page, the per-VMA reservation map entry remains marked as consumed, leading to a reservation leak. This leak can result in a subsequent fault at the same address taking the no-reservation path, potentially leading to a SIGBUS error if the hugetlb pool is under pressure.

Defensive priority

High priority should be given to applying patches that restore the reservation on error in hugetlb folio copy paths. System administrators should ensure that their Linux kernel versions are updated with the necessary fixes to prevent potential exploitation of this vulnerability.

Recommended defensive actions

  • Apply the official patches provided by the Linux kernel maintainers to restore the reservation on error in hugetlb folio copy paths.
  • Review and update Linux kernel versions to ensure they include the necessary fixes for CVE-2026-53154.
  • System administrators should monitor their systems for any unusual activity that could be related to this vulnerability.
  • Perform regular security audits and vulnerability assessments to identify and mitigate potential risks.
  • Consider implementing compensating controls, such as enhanced monitoring and exception tracking, until patches can be applied.

Evidence notes

The CVE record and associated details were obtained from the official CVE.org and NVD databases. Additional information was derived from source references provided in the NVD detail for CVE-2026-53154. The vulnerability description and technical details are based on the information available from these sources.

Official resources

This AI-assisted debrief is based on the supplied source corpus and official links. The information provided is intended for educational and defensive purposes only.