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🛡️ CVE-2023-52603 — kernel

🟠 CVSS 7.8 — High ✅ No Known Exploit NVD
7.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

UBSAN: array-index-out-of-bounds in dtSplitRoot

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

UBSAN: array-index-out-of-bounds in dtSplitRoot

Syzkaller reported the following issue:

oop0: detected capacity change from 0 to 32768

UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:1971:9

index -2 is out of range for type 'struct dtslot [128]'

CPU: 0 PID: 3613 Comm: syz-executor270 Not tainted 6.0.0-syzkaller-09423-g493ffd6605b2 #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022

Call Trace:

<TASK>

__dump_stack lib/dump_stack.c:88 [inline]

dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106

ubsan_epilogue lib/ubsan.c:151 [inline]

__ubsan_handle_out_of_bounds+0xdb/0x130 lib/ubsan.c:283

dtSplitRoot+0x8d8/0x1900 fs/jfs/jfs_dtree.c:1971

dtSplitUp fs/jfs/jfs_dtree.c:985 [inline]

dtInsert+0x1189/0x6b80 fs/jfs/jfs_dtree.c:863

jfs_mkdir+0x757/0xb00 fs/jfs/namei.c:270

vfs_mkdir+0x3b3/0x590 fs/namei.c:4013

do_mkdirat+0x279/0x550 fs/namei.c:4038

__do_sys_mkdirat fs/namei.c:4053 [inline]

__se_sys_mkdirat fs/namei.c:4051 [inline]

__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4051

do_syscall_x64 arch/x86/entry/common.c:50 [inline]

do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80

entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7fcdc0113fd9

Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007ffeb8bc67d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102

RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcdc0113fd9

RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003

RBP: 00007fcdc00d37a0 R08: 0000000000000000 R09: 00007fcdc00d37a0

R10: 00005555559a72c0 R11: 0000000000000246 R12: 00000000f8008000

R13: 0000000000000000 R14: 00083878000000f8 R15: 0000000000000000

</TASK>

The issue is caused when the value of fsi becomes less than -1.

The check to break the loop when fsi value becomes -1 is present

but syzbot was able to produce value less than -1 which cause the error.

This patch simply add the change for the values less than 0.

The patch is tested via syzbot.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Local — a local account, shell or session on the host is needed.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Affected software

CVE-2023-52603 is recorded against 2 packages.

  • kernel (from 6.7.0 up to 6.7.4)
  • linux-kernel (from 6.7 up to 6.7.4)

Timeline and source

Published on 6 March 2024 and last revised on 12 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
lists.debian.org (Web)
lists.debian.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

Other advisories for this package

kernel has other advisories on record. If you are patching this one, these are worth checking on the same host:

CVE-2023-52603 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity High
CVSS Score 7.8
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2024-03-06
Updated 2026-08-20
Modified 2026-08-12

Affected Packages

Software From version Fixed in
kernel 6.7.0 6.7.4
linux-kernel 6.7 6.7.4

References

Similar Threats

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