Executive Summary

Informations
Name CVE-2025-37785 First vendor Publication 2025-04-18
Vendor Cve Last vendor Modification 2025-05-02

Security-Database Scoring CVSS v3

Cvss vector : CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Overall CVSS Score 7.1
Base Score 7.1 Environmental Score 7.1
impact SubScore 5.2 Temporal Score 7.1
Exploitabality Sub Score 1.8
 
Attack Vector Local Attack Complexity Low
Privileges Required Low User Interaction None
Scope Unchanged Confidentiality Impact High
Integrity Impact None Availability Impact High
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector :
Cvss Base Score N/A Attack Range N/A
Cvss Impact Score N/A Attack Complexity N/A
Cvss Expoit Score N/A Authentication N/A
Calculate full CVSS 2.0 Vectors scores

Detail

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

ext4: fix OOB read when checking dotdot dir

Mounting a corrupted filesystem with directory which contains '.' dir entry with rec_len == block size results in out-of-bounds read (later on, when the corrupted directory is removed).

ext4_empty_dir() assumes every ext4 directory contains at least '.' and '..' as directory entries in the first data block. It first loads the '.' dir entry, performs sanity checks by calling ext4_check_dir_entry() and then uses its rec_len member to compute the location of '..' dir entry (in ext4_next_entry). It assumes the '..' dir entry fits into the same data block.

If the rec_len of '.' is precisely one block (4KB), it slips through the sanity checks (it is considered the last directory entry in the data block) and leaves "struct ext4_dir_entry_2 *de" point exactly past the memory slot allocated to the data block. The following call to ext4_check_dir_entry() on new value of de then dereferences this pointer which results in out-of-bounds mem access.

Fix this by extending __ext4_check_dir_entry() to check for '.' dir entries that reach the end of data block. Make sure to ignore the phony dir entries for checksum (by checking name_len for non-zero).

Note: This is reported by KASAN as use-after-free in case another structure was recently freed from the slot past the bound, but it is really an OOB read.

This issue was found by syzkaller tool.

Call Trace: [ 38.594108] BUG: KASAN: slab-use-after-free in __ext4_check_dir_entry+0x67e/0x710 [ 38.594649] Read of size 2 at addr ffff88802b41a004 by task syz-executor/5375 [ 38.595158] [ 38.595288] CPU: 0 UID: 0 PID: 5375 Comm: syz-executor Not tainted 6.14.0-rc7 #1 [ 38.595298] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 38.595304] Call Trace: [ 38.595308] [ 38.595311] dump_stack_lvl+0xa7/0xd0 [ 38.595325] print_address_description.constprop.0+0x2c/0x3f0 [ 38.595339] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595349] print_report+0xaa/0x250 [ 38.595359] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595368] ? kasan_addr_to_slab+0x9/0x90 [ 38.595378] kasan_report+0xab/0xe0 [ 38.595389] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595400] __ext4_check_dir_entry+0x67e/0x710 [ 38.595410] ext4_empty_dir+0x465/0x990 [ 38.595421] ? __pfx_ext4_empty_dir+0x10/0x10 [ 38.595432] ext4_rmdir.part.0+0x29a/0xd10 [ 38.595441] ? __dquot_initialize+0x2a7/0xbf0 [ 38.595455] ? __pfx_ext4_rmdir.part.0+0x10/0x10 [ 38.595464] ? __pfx___dquot_initialize+0x10/0x10 [ 38.595478] ? down_write+0xdb/0x140 [ 38.595487] ? __pfx_down_write+0x10/0x10 [ 38.595497] ext4_rmdir+0xee/0x140 [ 38.595506] vfs_rmdir+0x209/0x670 [ 38.595517] ? lookup_one_qstr_excl+0x3b/0x190 [ 38.595529] do_rmdir+0x363/0x3c0 [ 38.595537] ? __pfx_do_rmdir+0x10/0x10 [ 38.595544] ? strncpy_from_user+0x1ff/0x2e0 [ 38.595561] __x64_sys_unlinkat+0xf0/0x130 [ 38.595570] do_syscall_64+0x5b/0x180 [ 38.595583] entry_SYSCALL_64_after_hwframe+0x76/0x7e

Original Source

Url : http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-37785

CWE : Common Weakness Enumeration

% Id Name
100 % CWE-125 Out-of-bounds Read

CPE : Common Platform Enumeration

TypeDescriptionCount
Application 8
Os 3717

Sources (Detail)

https://git.kernel.org/stable/c/14da7dbecb430e35b5889da8dae7bef33173b351
https://git.kernel.org/stable/c/52a5509ab19a5d3afe301165d9b5787bba34d842
https://git.kernel.org/stable/c/53bc45da8d8da92ec07877f5922b130562eb4b00
https://git.kernel.org/stable/c/89503e5eae64637d0fa2218912b54660effe7d93
https://git.kernel.org/stable/c/ac28c5684c1cdab650a7e5065b19e91577d37a4b
https://git.kernel.org/stable/c/b47584c556444cf7acb66b26a62cbc348eb92b78
https://git.kernel.org/stable/c/b7531a4f99c3887439d778afaf418d1a01a5f01b
https://git.kernel.org/stable/c/d5e206778e96e8667d3bde695ad372c296dc9353
https://git.kernel.org/stable/c/e47f472a664d70a3d104a6c2a035cdff55a719b4
Source Url

Alert History

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Date Informations
2025-05-27 02:57:24
  • First insertion