medium CVSS 5.5

CVE-2024-38604·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: block: refine the EOF check in blkdev_iomap_begin blkdev_iomap_begin rounds down the offset to the logical block size before stashing it in iomap->offset and checking that it still is inside the inode size. Check the i_size check to the raw pos value so that we don't try a zero size write if iter->pos is unaligned.

Severity
medium
Software
Kernel
Fixed in
6.9.3
Published
2024-06-19

Affected versions

From: 6.9

Until: 6.9.3

Fixed in: 6.9.3

How to fix this CVE

Update your Linux kernel to version 6.9.3 or later to resolve this block device I/O mapping vulnerability. The fix refines the end-of-file (EOF) check in the blkdev_iomap_begin function to prevent unaligned write operations from causing denial of service conditions. Users running kernel versions 6.9 through 6.9.2 should prioritize this update to restore stability in block device operations.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check installed kernel version with `uname -r` and compare against 6.9.3 or later
  2. Step 2: Verify block device I/O operations are functioning by running `sudo blockdev --getsz /dev/sda` without errors
  3. Step 3: Search kernel logs for I/O mapping errors with `sudo journalctl -u kernel | grep -i 'iomap\|blkdev' | tail -50`
  4. Step 4: After patching, confirm the new kernel version loads with `uname -r` and verify block device operations resume normal behavior

FAQ

What is CVE-2024-38604?

CVE-2024-38604 is a Linux kernel vulnerability in the block device I/O mapping function that incorrectly handles unaligned file position values during write operations. This can lead to denial of service by allowing zero-sized writes or I/O failures when block offsets are not properly validated against file size boundaries.

Is CVE-2024-38604 being actively exploited?

No, this vulnerability is not listed on the CISA Known Exploited Vulnerabilities (KEV) catalog and there are no public exploits available. However, it remains a medium-severity issue that should be patched to prevent potential availability disruptions.

What versions of Kernel are affected by CVE-2024-38604?

Linux kernel versions 6.9 through 6.9.2 are vulnerable. Kernel 6.9.3 and later versions contain the fix and are safe to use.

How do I check if my server is vulnerable to CVE-2024-38604?

Run `uname -r` and check the kernel version. If it shows 6.9.0, 6.9.1, or 6.9.2, your system is vulnerable. Versions 6.9.3+ and all other stable branches (6.8, 6.10+) are not affected.

Does Defensia detect CVE-2024-38604?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2024-38604 will appear in your dashboard with remediation steps.

Related Kernel CVEs

CVE-2026-100075CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters When srpt_alloc_rw_ctxs() fails partway through a multi-buffer indirect descriptor, the unwind path destroys RDMA contexts but leaves stale n_rw_ctx and n_rdma values (and a dangling rw_ctxs pointer). Later sq_wr_avail accounting in srpt_queue_response() or srpt_write_pending() can then subtract the wrong number of send queue credits. Reset the counters and clear rw_ctxs after freeing the heap allocation before returning an error.
CVE-2026-64439CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: crypto: krb5 - filter out async aead implementations at alloc krb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and rfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL completion callback and treat any negative return from crypto_aead_{encrypt,decrypt}() as terminal, falling through to kfree_sensitive(buffer). When the encrypt_name resolves to an async AEAD instance the request returns -EINPROGRESS, the buffer is freed while the backend's worker still holds a pointer, and the worker dereferences the freed slab on completion. KASAN report under UML+SLUB with a synthetic async aead backend bound to krb5->encrypt_name: BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7 The helpers were written synchronously, so filter the async instances out at allocation time instead of plumbing crypto_wait_req() through every call site. Reachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and net/ceph/crypto.c on systems with an async AEAD provider bound to the krb5 enctype name.
CVE-2026-64066CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: netfs: Fix netfs_read_to_pagecache() to pause on subreq failure Fix netfs_read_to_pagecache() so that it pauses the generation of new subrequests if an already-issued subrequest fails.
CVE-2026-64383CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_flush() replay SMB2_flush() keeps its response buffer bookkeeping across replay attempts. If a replayable flush response is received and the retry then fails before cifs_send_recv() stores a replacement response, flush_exit will free the stale response pointer a second time. Reinitialize resp_buftype and rsp_iov at the top of the replay loop so cleanup only acts on response state produced by the current attempt. This fixes a double-free without changing replay handling for successful requests.
CVE-2026-64067CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: netfs: Fix missing barriers when accessing stream->subrequests locklessly The list of subrequests attached to stream->subrequests is accessed without locks by netfs_collect_read_results() and netfs_collect_write_results(), and then they access subreq->flags without taking a barrier after getting the subreq pointer from the list. Relatedly, the functions that build the list don't use any sort of write barrier when constructing the list to make sure that the NETFS_SREQ_IN_PROGRESS flag is perceived to be set first if no lock is taken. Fix this by: (1) Add a new list_add_tail_release() function that uses a release barrier to set the pointer to the new member of the list. (2) Add a new list_first_entry_or_null_acquire() function that uses an acquire barrier to read the pointer to the first member in a list (or return NULL). (3) Use list_add_tail_release() when adding a subreq to ->subrequests. (4) Use list_first_entry_or_null_acquire() when initially accessing the front of the list (when an item is removed, the pointer to the new front iterm is obtained under the same lock).

References

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