CVE-2026-53041

Description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix listxattr handling when the buffer is full [BUG] If an OCFS2 inode has both inline and block-based xattrs, listxattr() can return a size larger than the caller's buffer when the inline names consume that buffer exactly. kernel BUG at mm/usercopy.c:102! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI RIP: 0010:usercopy_abort+0xb7/0xd0 mm/usercopy.c:102 Call Trace: __check_heap_object+0xe3/0x120 mm/slub.c:8243 check_heap_object mm/usercopy.c:196 [inline] __check_object_size mm/usercopy.c:250 [inline] __check_object_size+0x5c5/0x780 mm/usercopy.c:215 check_object_size include/linux/ucopysize.h:22 [inline] check_copy_size include/linux/ucopysize.h:59 [inline] copy_to_user include/linux/uaccess.h:219 [inline] listxattr+0xb0/0x170 fs/xattr.c:926 filename_listxattr fs/xattr.c:958 [inline] path_listxattrat+0x137/0x320 fs/xattr.c:988 __do_sys_listxattr fs/xattr.c:1001 [inline] __se_sys_listxattr fs/xattr.c:998 [inline] __x64_sys_listxattr+0x7f/0xd0 fs/xattr.c:998 ... [CAUSE] Commit 936b8834366e ("ocfs2: Refactor xattr list and remove ocfs2_xattr_handler().") replaced the old per-handler list accounting with ocfs2_xattr_list_entry(), but it kept using size == 0 to detect probe mode. That assumption stops being true once ocfs2_listxattr() finishes the inline-xattr pass. If the inline names fill the caller buffer exactly, the block-xattr pass runs with a non-NULL buffer and a remaining size of zero. ocfs2_xattr_list_entry() then skips the bounds check, keeps counting block names, and returns a positive size larger than the supplied buffer. [FIX] Detect probe mode by testing whether the destination buffer pointer is NULL instead of whether the remaining size is zero. That restores the pre-refactor behavior and matches the OCFS2 getxattr helpers. Once the remaining buffer reaches zero while more names are left, the block-xattr pass now returns -ERANGE instead of reporting a size larger than the allocated list buffer.

CVSS v3.1 Score

7.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

EPSS — Exploit Prediction

0.0013

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/2323084c17370304f49c84b354fe7b3edbb264fe https://git.kernel.org/stable/c/2685df8577a38d83b367c8cf52eda9dc286959ff https://git.kernel.org/stable/c/46e66fefb83811958127bc9ad736983ec629d82b https://git.kernel.org/stable/c/50033ec1350fe68abdc63b950ced7ae57364b77a https://git.kernel.org/stable/c/6f702b00b8124c5d3525f19172934544826a114d https://git.kernel.org/stable/c/a35a1c2b170b5b578b1b3fecb95694796552af9a https://git.kernel.org/stable/c/d12f558e6200b3f47dbef9331ed6d115d2410e59 https://git.kernel.org/stable/c/d919b905939eda93393e3572900ff70dbad2b47f

Frequently Asked Questions

What is CVE-2026-53041? +

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix listxattr handling when the buffer is full [BUG] If an OCFS2 inode has both inline and block-based xattrs, listxattr() can return a size larger than the caller's buffer when the inline names consume that buffer exactly. kernel BUG at mm/usercopy.c:102! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI RIP: 0010:usercopy_abort+0xb7/0xd0 mm/usercopy.c:102 Call Trace: __check_heap_object+0xe3/0x120 mm/slub.c:8243 check_heap_object mm/usercopy.c:196 [inline] __check_object_size mm/usercopy.c:250 [inline] __check_object_size+0x5c5/0x780 mm/usercopy.c:215 check_object_size include/linux/ucopysize.h:22 [inline] check_copy_size include/linux/ucopysize.h:59 [inline] copy_to_user include/linux/uaccess.h:219 [inline] listxattr+0xb0/0x170 fs/xattr.c:926 filename_listxattr fs/xattr.c:958 [inline] path_listxattrat+0x137/0x320 fs/xattr.c:988 __do_sys_listxattr fs/xattr.c:1001 [inline] __se_sys_listxattr fs/xattr.c:998 [inline] __x64_sys_listxattr+0x7f/0xd0 fs/xattr.c:998 ... [CAUSE] Commit 936b8834366e ("ocfs2: Refactor xattr list and remove ocfs2_xattr_handler().") replaced the old per-handler list accounting with ocfs2_xattr_list_entry(), but it kept using size == 0 to detect probe mode. That assumption stops being true once ocfs2_listxattr() finishes the inline-xattr pass. If the inline names fill the caller buffer exactly, the block-xattr pass runs with a non-NULL buffer and a remaining size of zero. ocfs2_xattr_list_entry() then skips the bounds check, keeps counting block names, and returns a positive size larger than the supplied buffer. [FIX] Detect probe mode by testing whether the destination buffer pointer is NULL instead of whether the remaining size is zero. That restores the pre-refactor behavior and matches the OCFS2 getxattr helpers. Once the remaining buffer reaches zero while more names are left, the block-xattr pass now returns -ERANGE instead of reporting a size larger than the allocated list buffer. It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2026-53041? +

CVE-2026-53041 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0013, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-53041? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.