Linux Kernel up to 6.1.28 clear_page_64.S clear_user_rep_good memory corruption

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 6.1.28. Affected by this issue is the function clear_user_rep_good in the library arch/x86/lib/clear_page_64.S. Performing a manipulation results in memory corruption. This vulnerability is identified as CVE-2023-53642. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.28. It has been classified as critical. This affects the function clear_user_rep_good in the library arch/x86/lib/clear_page_64.S. The manipulation with an unknown input leads to a memory corruption vulnerability. CWE is classifying the issue as CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: x86: fix clear_user_rep_good() exception handling annotation This code no longer exists in mainline, because it was removed in commit d2c95f9d6802 ("x86: don't use REP_GOOD or ERMS for user memory clearing") upstream. However, rather than backport the full range of x86 memory clearing and copying cleanups, fix the exception table annotation placement for the final 'rep movsb' in clear_user_rep_good(): rather than pointing at the actual instruction that did the user space access, it pointed to the register move just before it. That made sense from a code flow standpoint, but not from an actual usage standpoint: it means that if user access takes an exception, the exception handler won't actually find the instruction in the exception tables. As a result, rather than fixing it up and returning -EFAULT, it would then turn it into a kernel oops report instead, something like: BUG: unable to handle page fault for address: 0000000020081000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page ... RIP: 0010:clear_user_rep_good+0x1c/0x30 arch/x86/lib/clear_page_64.S:147 ... Call Trace: __clear_user arch/x86/include/asm/uaccess_64.h:103 [inline] clear_user arch/x86/include/asm/uaccess_64.h:124 [inline] iov_iter_zero+0x709/0x1290 lib/iov_iter.c:800 iomap_dio_hole_iter fs/iomap/direct-io.c:389 [inline] iomap_dio_iter fs/iomap/direct-io.c:440 [inline] __iomap_dio_rw+0xe3d/0x1cd0 fs/iomap/direct-io.c:601 iomap_dio_rw+0x40/0xa0 fs/iomap/direct-io.c:689 ext4_dio_read_iter fs/ext4/file.c:94 [inline] ext4_file_read_iter+0x4be/0x690 fs/ext4/file.c:145 call_read_iter include/linux/fs.h:2183 [inline] do_iter_readv_writev+0x2e0/0x3b0 fs/read_write.c:733 do_iter_read+0x2f2/0x750 fs/read_write.c:796 vfs_readv+0xe5/0x150 fs/read_write.c:916 do_preadv+0x1b6/0x270 fs/read_write.c:1008 __do_sys_preadv2 fs/read_write.c:1070 [inline] __se_sys_preadv2 fs/read_write.c:1061 [inline] __x64_sys_preadv2+0xef/0x150 fs/read_write.c:1061 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd which then looks like a filesystem bug rather than the incorrect exception annotation that it is. [ The alternative to this one-liner fix is to take the upstream series that cleans this all up: 68674f94ffc9 ("x86: don't use REP_GOOD or ERMS for small memory copies") 20f3337d350c ("x86: don't use REP_GOOD or ERMS for small memory clearing") adfcf4231b8c ("x86: don't use REP_GOOD or ERMS for user memory copies") * d2c95f9d6802 ("x86: don't use REP_GOOD or ERMS for user memory clearing") 3639a535587d ("x86: move stac/clac from user copy routines into callers") 577e6a7fd50d ("x86: inline the 'rep movs' in user copies for the FSRM case") 8c9b6a88b7e2 ("x86: improve on the non-rep 'clear_user' function") 427fda2c8a49 ("x86: improve on the non-rep 'copy_user' function") * e046fe5a36a9 ("x86: set FSRS automatically on AMD CPUs that have FSRM") e1f2750edc4a ("x86: remove 'zerorest' argument from __copy_user_nocache()") 034ff37d3407 ("x86: rewrite '__copy_user_nocache' function") with either the whole series or at a minimum the two marked commits being needed to fix this issue ]

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2023-53642 since 10/07/2025. The exploitability is told to be easy. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 03/01/2026).

Upgrading to version 6.1.29 eliminates this vulnerability. Applying the patch 76ce32682635fe907e0f8e64e039e773e5c7508f is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at EUVD (EUVD-2025-31956) and CERT Bund (WID-SEC-2025-2229). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Amazon Linux 2
• Red Hat Enterprise Linux
• SUSE Linux
• Oracle Linux
• RESF Rocky Linux
• Open Source Linux Kernel
• IBM QRadar SIEM
• Dell NetWorker

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.1.20
• 6.1.21
• 6.1.22
• 6.1.23
• 6.1.24
• 6.1.25
• 6.1.26
• 6.1.27
• 6.1.28

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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