Transaction Overflow Vulnerability in Linux Kernel's ext4 Product by Linux Foundation

CVE-2026-100073

What is CVE-2026-100073?

In the Linux kernel, a vulnerability has been identified related to transaction overflow during the writeback process of the ext4 filesystem. The issue arises when insufficient transaction credits are allocated for extent conversions, particularly with large folios that may require multiple modifications. The commit intended to reserve enough credits for various extents; however, it mistakenly reduced the necessary number of reserved credits. In specific scenarios, this misallocation can lead to inadequate resources during complex operations such as extent splitting or allocation of new extent tree nodes. Utilizing the ext4_meta_trans_blocks() function can help provide a more accurate estimate of the upper bound for required transaction credits, thus mitigating the risk of this vulnerability.

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