CVE-2026-23416mm/mseal: update VMA end correctly on merge

Official description

In the Linux kernel, the following vulnerability has been resolved: mm/mseal: update VMA end correctly on merge Previously we stored the end of the current VMA in curr_end, and then upon iterating to the next VMA updated curr_start to curr_end to advance to the next VMA. However, this doesn't take into account the fact that a VMA might be updated due to a merge by vma_modify_flags(), which can result in curr_end being stale and thus, upon setting curr_start to curr_end, ending up with an incorrect curr_start on the next iteration. Resolve the issue by setting curr_end to vma->vm_end unconditionally to ensure this value remains updated should this occur. While we're here, eliminate this entire class of bug by simply setting const curr_[start/end] to be clamped to the input range and VMAs, which also happens to simplify the logic.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/40b3f4700e5535fbe74738cebb9379a40ec66bed
• https://git.kernel.org/stable/c/83737e34b83a23b2a9bcf586b058b2c2a54c7c6b
• https://git.kernel.org/stable/c/2697dd8ae721db4f6a53d4f4cbd438212a80f8dc