Time-of-check Time-of-use (TOCTOU) The advisory has been revoked - it doesn't affect any version of package rv  (opens in a new tab)


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  • Snyk IDSNYK-RHEL10-RV-16953577
  • published28 May 2026
  • disclosed27 May 2026

Introduced: 27 May 2026

CVE-2026-45892  (opens in a new tab)
CWE-367  (opens in a new tab)

Amendment

The Red Hat security team deemed this advisory irrelevant for RHEL:10.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rv package and not the rv package as distributed by RHEL.

In the Linux kernel, the following vulnerability has been resolved:

ext4: drop extent cache after doing PARTIAL_VALID1 zeroout

When splitting an unwritten extent in the middle and converting it to initialized in ext4_split_extent() with the EXT4_EXT_MAY_ZEROOUT and EXT4_EXT_DATA_VALID2 flags set, it could leave a stale unwritten extent.

Assume we have an unwritten file and buffered write in the middle of it without dioread_nolock enabled, it will allocate blocks as written extent.

   0  A      B  N
   [UUUUUUUUUUUU] on-disk extent      U: unwritten extent
   [UUUUUUUUUUUU] extent status tree
   [--DDDDDDDD--]                     D: valid data
      |<-  ->| ----> this range needs to be initialized

ext4_split_extent() first try to split this extent at B with EXT4_EXT_DATA_PARTIAL_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but ext4_split_extent_at() failed to split this extent due to temporary lack of space. It zeroout B to N and leave the entire extent as unwritten.

   0  A      B  N
   [UUUUUUUUUUUU] on-disk extent
   [UUUUUUUUUUUU] extent status tree
   [--DDDDDDDDZZ]                     Z: zeroed data

ext4_split_extent() then try to split this extent at A with EXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and leave an written extent from A to N.

   0  A      B  N
   [UUWWWWWWWWWW] on-disk extent      W: written extent
   [UUUUUUUUUUUU] extent status tree
   [--DDDDDDDDZZ]

Finally ext4_map_create_blocks() only insert extent A to B to the extent status tree, and leave an stale unwritten extent in the status tree.

   0  A      B  N
   [UUWWWWWWWWWW] on-disk extent      W: written extent
   [UUWWWWWWWWUU] extent status tree
   [--DDDDDDDDZZ]

Fix this issue by always cached extent status entry after zeroing out the second part.