CVE-2026-72367: Linux Vulnerability (CVSS 8.8)

Description

In the Linux kernel, the following vulnerability has been resolved: iomap: guard io_size EOF trim against concurrent truncate underflow iomap: fix zero padding data issue in concurrent append writes changed ioend accounting so that io_size tracks only valid data within EOF. This trims io_size when a writeback range extends past end_pos: ioend->io_size += map_len; if (ioend->io_offset + ioend->io_size > end_pos) ioend->io_size = end_pos - ioend->io_offset; However, if end_pos ends up below ioend->io_offset, the subtraction becomes negative and is stored in size_t io_size, causing an unsigned wrap to a huge value. This can happen when writeback continues past byte-level EOF up to a block-aligned range, or when a concurrent truncate shrinks the file after end_pos was sampled in iomap_writeback_handle_eof(). A wrapped io_size can mislead append detection and corrupt completion-time size handling, since filesystem end_io paths consume io_size for decisions such as on-disk EOF updates and unwritten/COW completion ranges. Fix this by clamping io_size to zero when EOF has moved to or before the ioend start offset. This preserves the original intent of trimming io_size to valid in-EOF data while avoiding the underflow.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.21%

11.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 51d20d1dacbec589d459e11fc88fbca419f84a99, < 1f38f65bf965fce9aa159d45c5347538f56c5973; >= 51d20d1dacbec589d459e11fc88fbca419f84a99, < 7f7780abb4c0fdc9a2603aea8e985ff14ee900e0; >= 51d20d1dacbec589d459e11fc88fbca419f84a99, < 55ec50d046c03b3724741957f7b007856e36dbe7; 82c59a86a247a8970d353d10f52a37e5564fb137; >= 6.12.10, < 6.13
Linux	Linux	6.13

References

Timeline

Published: Aug 15, 2026
Last Modified: Aug 17, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-72367?

In the Linux kernel, the following vulnerability has been resolved: iomap: guard io_size EOF trim against concurrent truncate underflow iomap: fix zero padding data issue in concurrent append writes changed ioend accounting so that io_size tracks only valid data within EOF. This trims io_size when a writeback range extends past end_pos: ioend->io_size += map_len; if (ioend->io_offset + ioend->io_size > end_pos) ioend->io_size = end_pos - ioend->io_offset; However, if end_pos ends up below ioend->io_offset, the subtraction becomes negative and is stored in size_t io_size, causing an unsigned wrap to a huge value. This can happen when writeback continues past byte-level EOF up to a block-aligned range, or when a concurrent truncate shrinks the file after end_pos was sampled in iomap_writeback_handle_eof(). A wrapped io_size can mislead append detection and corrupt completion-time size handling, since filesystem end_io paths consume io_size for decisions such as on-disk EOF updates and unwritten/COW completion ranges. Fix this by clamping io_size to zero when EOF has moved to or before the ioend start offset. This preserves the original intent of trimming io_size to valid in-EOF data while avoiding the underflow.

How severe is CVE-2026-72367?

CVE-2026-72367 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2026-72367?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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