# CVE-2025-37780: isofs: Prevent the use of too small fid

> A local attacker can trigger a slab-out-of-bounds read in the Linux kernel's isofs filesystem, potentially causing a crash or leaking memory.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 May 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-37780, DEBIAN-CVE-2025-37780, GHSA-w595-4hr6-r5fv, ROOT-OS-DEBIAN-12-CVE-2025-37780, ROOT-OS-UBUNTU-2204-CVE-2025-37780, ROOT-OS-UBUNTU-2404-CVE-2025-37780, UBUNTU-CVE-2025-37780

## What is CVE-2025-37780?

CVE-2025-37780 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 1 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

isofs: Prevent the use of too small fid

syzbot reported a slab-out-of-bounds Read in isofs_fh_to_parent. [1]

The handle_bytes value passed in by the reproducing program is equal to 12.
In handle_to_path(), only 12 bytes of memory are allocated for the structure
file_handle->f_handle member, which causes an out-of-bounds access when
accessing the member parent_block of the structure isofs_fid in isofs,
because accessing parent_block requires at least 16 bytes of f_handle.
Here, fh_len is used to indirectly confirm that the value of handle_bytes
is greater than 3 before accessing parent_block.

[1]
BUG: KASAN: slab-out-of-bounds in isofs_fh_to_parent+0x1b8/0x210 fs/isofs/export.c:183
Read of size 4 at addr ffff0000cc030d94 by task syz-executor215/6466
CPU: 1 UID: 0 PID: 6466 Comm: syz-executor215 Not tainted 6.14.0-rc7-syzkaller-ga2392f333575 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0x198/0x550 mm/kasan/report.c:521
 kasan_report+0xd8/0x138 mm/kasan/report.c:634
 __asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
 isofs_fh_to_parent+0x1b8/0x210 fs/isofs/export.c:183
 exportfs_decode_fh_raw+0x2dc/0x608 fs/exportfs/expfs.c:523
 do_handle_to_path+0xa0/0x198 fs/fhandle.c:257
 handle_to_path fs/fhandle.c:385 [inline]
 do_handle_open+0x8cc/0xb8c fs/fhandle.c:403
 __do_sys_open_by_handle_at fs/fhandle.c:443 [inline]
 __se_sys_open_by_handle_at fs/fhandle.c:434 [inline]
 __arm64_sys_open_by_handle_at+0x80/0x94 fs/fhandle.c:434
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

Allocated by task 6466:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:562
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xac/0xc4 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4294 [inline]
 __kmalloc_noprof+0x32c/0x54c mm/slub.c:4306
 kmalloc_noprof include/linux/slab.h:905 [inline]
 handle_to_path fs/fhandle.c:357 [inline]
 do_handle_open+0x5a4/0xb8c fs/fhandle.c:403
 __do_sys_open_by_handle_at fs/fhandle.c:443 [inline]
 __se_sys_open_by_handle_at fs/fhandle.c:434 [inline]
 __arm64_sys_open_by_handle_at+0x80/0x94 fs/fhandle.c:434
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2025-37780?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-37780?

Apply the vendor's patch.

## Is CVE-2025-37780 being exploited?

There is no known exploitation of CVE-2025-37780 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-37780 and fix it if it is affected.

What it is: CVE-2025-37780 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 1 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-37780 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-37780/ (Markdown: https://insights.sbomify.com/CVE-2025-37780/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-37780
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-37780
- OSV: https://osv.dev/vulnerability/CVE-2025-37780

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-37780/
Summaries are generated and may contain mistakes; the official description above is the record.
