7.8

CVE-2025-23150: ext4: fix off-by-one error in do_split

Modified
AliasesUBUNTU-CVE-2025-23150DEBIAN-CVE-2025-23150
Published 01-05-2025Last modified 05-08-2026

Vulnerability summary

CVE-2025-23150 is a high (CVSS 7.8) Off-by-one Error vulnerability in debian debian_linux. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 14.1% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.23%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 57 · Related 41
DLA-4178-1DLA-4193-1RHSA-2025:11245RHSA-2025:11298RHSA-2025:11299RHSA-2025:11571

Timeline

  1. 01-05-2025
    PublishedVulnerability first disclosed.
  2. 05-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: fix off-by-one error in do_split Syzkaller detected a use-after-free issue in ext4_insert_dentry that was caused by out-of-bounds access due to incorrect splitting in do_split. BUG: KASAN: use-after-free in ext4_insert_dentry+0x36a/0x6d0 fs/ext4/namei.c:2109 Write of size 251 at addr ffff888074572f14 by task syz-executor335/5847 CPU: 0 UID: 0 PID: 5847 Comm: syz-executor335 Not tainted 6.12.0-rc6-syzkaller-00318-ga9cda7c0ffed #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189 __asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106 ext4_insert_dentry+0x36a/0x6d0 fs/ext4/namei.c:2109 add_dirent_to_buf+0x3d9/0x750 fs/ext4/namei.c:2154 make_indexed_dir+0xf98/0x1600 fs/ext4/namei.c:2351 ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2455 ext4_add_nondir+0x8d/0x290 fs/ext4/namei.c:2796 ext4_symlink+0x920/0xb50 fs/ext4/namei.c:3431 vfs_symlink+0x137/0x2e0 fs/namei.c:4615 do_symlinkat+0x222/0x3a0 fs/namei.c:4641 __do_sys_symlink fs/namei.c:4662 [inline] __se_sys_symlink fs/namei.c:4660 [inline] __x64_sys_symlink+0x7a/0x90 fs/namei.c:4660 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> The following loop is located right above 'if' statement. for (i = count-1; i >= 0; i--) { /* is more than half of this entry in 2nd half of the block? */ if (size + map[i].size/2 > blocksize/2) break; size += map[i].size; move++; } 'i' in this case could go down to -1, in which case sum of active entries wouldn't exceed half the block size, but previous behaviour would also do split in half if sum would exceed at the very last block, which in case of having too many long name files in a single block could lead to out-of-bounds access and following use-after-free. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.23%

Chance of exploitation in the next 30 days

Percentile

14%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.23% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu138 products
  • linuxAll versions (No fix recorded) | < 5.15.0-144.157 | < 6.8.0-100.100
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1088.95 | < 6.8.0-1046.49
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian2 products
Linux2 products
  • linux≥ ea54176e5821936d109bb45dc2c19bd53559e735, < b96bd2c3db26ad0daec5b78c85c098b53900e2e1 | ≥ 5872331b3d91820e14716632ebb56b1399b34fe1, < 515c34cff899eb5dae6aa7eee01c1295b07d81af | ≥ 5872331b3d91820e14716632ebb56b1399b34fe1, < 2883e9e74f73f9265e5f8d1aaaa89034b308e433 | ≥ 5872331b3d91820e14716632ebb56b1399b34fe1, < 35d0aa6db9d93307085871ceab8a729594a98162 | ≥ 5872331b3d91820e14716632ebb56b1399b34fe1, < 2eeb1085bf7bd5c7ba796ca4119925fa5d336a3f | ≥ 5872331b3d91820e14716632ebb56b1399b34fe1, < 16d9067f00e3a7d1df7c3aa9c20d214923d27e10 | ≥ 5872331b3d91820e14716632ebb56b1399b34fe1, < 17df39f455f1289319d4d09e4826aa46852ffd17 | ≥ 5872331b3d91820e14716632ebb56b1399b34fe1, < ab0cc5c25552ae0d20eae94b40a93be11b080fc5 | ≥ 5872331b3d91820e14716632ebb56b1399b34fe1, < 94824ac9a8aaf2fb3c54b4bdde842db80ffa555d | 059b1480105478c5f68cf664301545b8cad6a7cf | 539ae3e03875dacaa9c388aff141ccbb4ef4ecb5 | fbbfd55a40d5d0806b59ee0403c75d5ac517533f | b3ddf6ba5e28a57729fff1605ae08e21be5c92e3 | e50fe43e3062e18846e99d9646b9c07b097eb1ed | 88e79f7a9841278fa8ff7ff6178bad12da002ffc | ≥ 5.4.61, < 5.4.293 | ≥ 4.4.234, < 4.5 | ≥ 4.9.234, < 4.10 | ≥ 4.14.195, < 4.15 | ≥ 4.19.142, < 4.20 | ≥ 5.7.18, < 5.8 | ≥ 5.8.4, < 5.9 | 5.9
  • linux_kernel≥ 4.4.234, < 4.5 | ≥ 4.9.234, < 4.10 | ≥ 4.14.195, < 4.15 | ≥ 4.19.142, < 4.20 | ≥ 5.4.61, < 5.4.293 | ≥ 5.7.18, < 5.8 | ≥ 5.8.4, < 5.9 | ≥ 5.9.1, < 5.10.237 | ≥ 5.11, < 5.15.181 | ≥ 5.16, < 6.1.135 | ≥ 6.2, < 6.6.88 | ≥ 6.7, < 6.12.24 | ≥ 6.13, < 6.13.12 | ≥ 6.14, < 6.14.3 | 5.9 | 5.9:rc2 | 5.9:rc3 | 5.9:rc4 | 5.9:rc5 | 5.9:rc6 | 5.9:rc7 | 5.9:rc8 | 6.15:rc1

3 vendors · 142 products

References

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