Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: fix out of bounds...
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix out of bounds punch offset
Punching a hole with a start offset that exceeds max_end is not
permitted and will result in a negative length in the
truncate_inode_partial_folio() function while truncating the page cache,
potentially leading to undesirable consequences.
A simple reproducer:
truncate -s 9895604649994 /mnt/foo
xfs_io -c "pwrite 8796093022208 4096" /mnt/foo
xfs_io -c "fpunch 8796093022213 25769803777" /mnt/foo
kernel BUG at include/linux/highmem.h:275!
Oops: invalid opcode: 0000 [#1] SMP PTI
CPU: 3 UID: 0 PID: 710 Comm: xfs_io Not tainted 6.15.0-rc3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
RIP: 0010:zero_user_segments.constprop.0+0xd7/0x110
RSP: 0018:ffffc90001cf3b38 EFLAGS: 00010287
RAX: 0000000000000005 RBX: ffffea0001485e40 RCX: 0000000000001000
RDX: 000000000040b000 RSI: 0000000000000005 RDI: 000000000040b000
RBP: 000000000040affb R08: ffff888000000000 R09: ffffea0000000000
R10: 0000000000000003 R11: 00000000fffc7fc5 R12: 0000000000000005
R13: 000000000040affb R14: ffffea0001485e40 R15: ffff888031cd3000
FS: 00007f4f63d0b780(0000) GS:ffff8880d337d000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000001ae0b038 CR3: 00000000536aa000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
truncate_inode_partial_folio+0x3dd/0x620
truncate_inode_pages_range+0x226/0x720
? bdev_getblk+0x52/0x3e0
? ext4_get_group_desc+0x78/0x150
? crc32c_arch+0xfd/0x180
? __ext4_get_inode_loc+0x18c/0x840
? ext4_inode_csum+0x117/0x160
? jbd2_journal_dirty_metadata+0x61/0x390
? __ext4_handle_dirty_metadata+0xa0/0x2b0
? kmem_cache_free+0x90/0x5a0
? jbd2_journal_stop+0x1d5/0x550
? __ext4_journal_stop+0x49/0x100
truncate_pagecache_range+0x50/0x80
ext4_truncate_page_cache_block_range+0x57/0x3a0
ext4_punch_hole+0x1fe/0x670
ext4_fallocate+0x792/0x17d0
? __count_memcg_events+0x175/0x2a0
vfs_fallocate+0x121/0x560
ksys_fallocate+0x51/0xc0
__x64_sys_fallocate+0x24/0x40
x64_sys_call+0x18d2/0x4170
do_syscall_64+0xa7/0x220
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fix this by filtering out cases where the punching start offset exceeds
max_end.
Impact
A read operation accesses a memory location beyond the intended buffer boundary. Typical impact: sensitive data disclosure or crash.
CVE-2025-38221 has a CVSS score of 7.1 (High). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-38221? CVE-2025-38221 is a high-severity out-of-bounds read vulnerability. No fixed version is listed yet. A read operation accesses a memory location beyond the intended buffer boundary.
- How severe is CVE-2025-38221? CVE-2025-38221 has a CVSS score of 7.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-38221? No fixed version is listed for CVE-2025-38221 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-38221 exploitable, and should I be worried? Whether CVE-2025-38221 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-38221 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.