# CVE-2026-23265: f2fs: fix to do sanity check on node footer in {read,write}_end_io

CVE-2026-23265 is fixed in linux on 1 platform by DEBIAN-CVE-2026-23265 (version 6.18.13-1), released March 18, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-23265
- Priority: High
- CVSS: 7.1 (Important)
- EPSS: 0.0012
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 18, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-23265

## Description

In the Linux kernel, the following vulnerability has been resolved:  f2fs: fix to do sanity check on node footer in {read,write}_end_io  -----------[ cut here ]------------ kernel BUG at fs/f2fs/data.c:358! Call Trace:  <IRQ>  blk_update_request+0x5eb/0xe70 block/blk-mq.c:987  blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1149  blk_complete_reqs block/blk-mq.c:1224 [inline]  blk_done_softirq+0x107/0x160 block/blk-mq.c:1229  handle_softirqs+0x283/0x870 kernel/softirq.c:579  __do_softirq kernel/softirq.c:613 [inline]  invoke_softirq kernel/softirq.c:453 [inline]  __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680  irq_exit_rcu+0x9/0x30 kernel/softirq.c:696  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]  sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050  </IRQ>  In f2fs_write_end_io(), it detects there is inconsistency in between node page index (nid) and footer.nid of node page.  If footer of node page is corrupted in fuzzed image, then we load corrupted node page w/ async method, e.g. f2fs_ra_node_pages() or f2fs_ra_node_page(), in where we won't do sanity check on node footer, once node page becomes dirty, we will encounter this bug after node page writeback.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.18.13-1 | [DEBIAN-CVE-2026-23265](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23265.md) | Mar 18, 2026 |

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