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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-45984

gfs2: Fix use-after-free in iomap inline data write path

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix use-after-free in iomap inline data write path The inline data buffer head (dibh) is being released prematurely in gfs2_iomap_begin() via release_metapath() while iomap->inline_data still points to dibh->b_data. This causes a use-after-free when iomap_write_end_inline() later attempts to write to the inline data area. The bug sequence: 1. gfs2_iomap_begin() calls gfs2_meta_inode_buffer() to read inode metadata into dibh 2. Sets iomap->inline_data = dibh->b_data + sizeof(struct gfs2_dinode) 3. Calls release_metapath() which calls brelse(dibh), dropping refcount to 0 4. kswapd reclaims the page (~39ms later in the syzbot report) 5. iomap_write_end_inline() tries to memcpy() to iomap->inline_data 6. KASAN detects use-after-free write to freed memory Fix by storing dibh in iomap->private and incrementing its refcount with get_bh() in gfs2_iomap_begin(). The buffer is then properly released in gfs2_iomap_end() after the inline write completes, ensuring the page stays alive for the entire iomap operation. Note: A C reproducer is not available for this issue. The fix is based on analysis of the KASAN report and code review showing the buffer head is freed before use. [agruenba: Take buffer head reference in gfs2_iomap_begin() to avoid leaks in gfs2_iomap_get() and gfs2_iomap_alloc().]

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • d0a22a4b03b8475b7aa3fa41243c26c291407844 to < 1403989d1b502f4a2c0d0b42ccf1c25748442effaffected
  • d0a22a4b03b8475b7aa3fa41243c26c291407844 to < 1cae1bafdf9caa9b462b19af06b1a06902e4e142affected
  • d0a22a4b03b8475b7aa3fa41243c26c291407844 to < 764c3c84b5683e608f43735c803a5f415046686caffected
  • d0a22a4b03b8475b7aa3fa41243c26c291407844 to < d87268326b277af3665237ac76a73dd9fa8e21b4affected
  • d0a22a4b03b8475b7aa3fa41243c26c291407844 to < 87d4954b5c59735a99ea98cb208d47130f6dce7daffected
  • d0a22a4b03b8475b7aa3fa41243c26c291407844 to < 6d76febba07c40bcf358f63216d36ea68cf1c215affected
  • d0a22a4b03b8475b7aa3fa41243c26c291407844 to < 815ddd27c0c7171a99fe802fdb19098ddef8b19daffected
  • d0a22a4b03b8475b7aa3fa41243c26c291407844 to < faddeb848305e79db89ee0479bb0e33380656321affected

Linux Linux

Default version status: affected

  • 5.2affected
  • 0 to < 5.2unaffected
  • 5.10.252 to ≤ 5.10.*unaffected
  • 5.15.202 to ≤ 5.15.*unaffected
  • 6.1.165 to ≤ 6.1.*unaffected
  • 6.6.128 to ≤ 6.6.*unaffected
  • 6.12.75 to ≤ 6.12.*unaffected
  • 6.18.14 to ≤ 6.18.*unaffected
  • 6.19.4 to ≤ 6.19.*unaffected
  • 7.0 to ≤ *unaffected

References