CVE-2026-45984
published 2026-05-27CVE-2026-45984: 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)…
high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
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
10 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| linux | linux | — | — |
| linux | linux | >= d0a22a4b03b8475b7aa3fa41243c26c291407844 < 1403989d1b502f4a2c0d0b42ccf1c25748442eff | 1403989d1b502f4a2c0d0b42ccf1c25748442eff |
| linux | linux | >= d0a22a4b03b8475b7aa3fa41243c26c291407844 < 1cae1bafdf9caa9b462b19af06b1a06902e4e142 | 1cae1bafdf9caa9b462b19af06b1a06902e4e142 |
| linux | linux | >= d0a22a4b03b8475b7aa3fa41243c26c291407844 < 764c3c84b5683e608f43735c803a5f415046686c | 764c3c84b5683e608f43735c803a5f415046686c |
| linux | linux | >= d0a22a4b03b8475b7aa3fa41243c26c291407844 < d87268326b277af3665237ac76a73dd9fa8e21b4 | d87268326b277af3665237ac76a73dd9fa8e21b4 |
| linux | linux | >= d0a22a4b03b8475b7aa3fa41243c26c291407844 < 87d4954b5c59735a99ea98cb208d47130f6dce7d | 87d4954b5c59735a99ea98cb208d47130f6dce7d |
| linux | linux | >= d0a22a4b03b8475b7aa3fa41243c26c291407844 < 6d76febba07c40bcf358f63216d36ea68cf1c215 | 6d76febba07c40bcf358f63216d36ea68cf1c215 |
| linux | linux | >= d0a22a4b03b8475b7aa3fa41243c26c291407844 < 815ddd27c0c7171a99fe802fdb19098ddef8b19d | 815ddd27c0c7171a99fe802fdb19098ddef8b19d |
| linux | linux | >= d0a22a4b03b8475b7aa3fa41243c26c291407844 < faddeb848305e79db89ee0479bb0e33380656321 | faddeb848305e79db89ee0479bb0e33380656321 |
| linux | linux_kernel | — | — |