high CVSS 7.8

CVE-2024-26842·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: scsi: ufs: core: Fix shift issue in ufshcd_clear_cmd() When task_tag >= 32 (in MCQ mode) and sizeof(unsigned int) == 4, 1U << task_tag will out of bounds for a u32 mask. Fix this up to prevent SHIFT_ISSUE (bitwise shifts that are out of bounds for their data type). [name:debug_monitors&]Unexpected kernel BRK exception at EL1 [name:traps&]Internal error: BRK handler: 00000000f2005514 [#1] PREEMPT SMP [name:mediatek_cpufreq_hw&]cpufreq stop DVFS log done [name:mrdump&]Kernel Offset: 0x1ba5800000 from 0xffffffc008000000 [name:mrdump&]PHYS_OFFSET: 0x80000000 [name:mrdump&]pstate: 22400005 (nzCv daif +PAN -UAO) [name:mrdump&]pc : [0xffffffdbaf52bb2c] ufshcd_clear_cmd+0x280/0x288 [name:mrdump&]lr : [0xffffffdbaf52a774] ufshcd_wait_for_dev_cmd+0x3e4/0x82c [name:mrdump&]sp : ffffffc0081471b0 <snip> Workqueue: ufs_eh_wq_0 ufshcd_err_handler Call trace: dump_backtrace+0xf8/0x144 show_stack+0x18/0x24 dump_stack_lvl+0x78/0x9c dump_stack+0x18/0x44 mrdump_common_die+0x254/0x480 [mrdump] ipanic_die+0x20/0x30 [mrdump] notify_die+0x15c/0x204 die+0x10c/0x5f8 arm64_notify_die+0x74/0x13c do_debug_exception+0x164/0x26c el1_dbg+0x64/0x80 el1h_64_sync_handler+0x3c/0x90 el1h_64_sync+0x68/0x6c ufshcd_clear_cmd+0x280/0x288 ufshcd_wait_for_dev_cmd+0x3e4/0x82c ufshcd_exec_dev_cmd+0x5bc/0x9ac ufshcd_verify_dev_init+0x84/0x1c8 ufshcd_probe_hba+0x724/0x1ce0 ufshcd_host_reset_and_restore+0x260/0x574 ufshcd_reset_and_restore+0x138/0xbd0 ufshcd_err_handler+0x1218/0x2f28 process_one_work+0x5fc/0x1140 worker_thread+0x7d8/0xe20 kthread+0x25c/0x468 ret_from_fork+0x10/0x20

Severity
high
Software
Kernel
Fixed in
6.7.7
Published
2024-04-17

Affected versions

From: 6.7

Until: 6.7.7

Fixed in: 6.7.7

How to fix this CVE

Update your Linux kernel to version 6.7.7 or later to resolve a critical bitwise shift vulnerability in the UFS (Ultra Fast Storage) subsystem. This vulnerability affects multi-queue (MCQ) mode operations where task tags >= 32 cause out-of-bounds bit shifts in the ufshcd_clear_cmd() function, potentially triggering kernel panics. Apply the patch immediately on systems using UFS storage controllers.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check your kernel version with `uname -r` and compare against 6.7.7 — versions 6.7.0 through 6.7.6 are vulnerable
  2. Step 2: Verify UFS subsystem is in use by running `lsmod | grep ufs` — if output appears, the affected driver is loaded
  3. Step 3: Search kernel logs for panic indicators with `dmesg | grep -i 'ufshcd_clear_cmd\|SHIFT_ISSUE\|BRK exception'` to identify past exploitation attempts
  4. Step 4: After patching, reboot the system with `sudo reboot` and confirm new kernel version with `uname -r` to verify the fix is active

FAQ

What is CVE-2024-26842?

CVE-2024-26842 is a kernel memory safety vulnerability in the Linux UFS storage driver where a bitwise shift operation exceeds the data type boundary when handling task tags in multi-queue mode (task_tag >= 32 on 32-bit systems). This triggers a kernel BRK exception and causes the system to panic.

Is CVE-2024-26842 being actively exploited?

No, CVE-2024-26842 is not listed in CISA's Known Exploited Vulnerabilities catalog and has no public exploit code available. However, it causes immediate kernel crashes on affected systems, making it a high-priority stability issue.

What versions of Kernel are affected by CVE-2024-26842?

Linux kernel versions 6.7.0 through 6.7.6 are vulnerable. The fix is included in kernel 6.7.7 and later stable releases.

How do I check if my server is vulnerable to CVE-2024-26842?

Run `uname -r` to get your kernel version. If it shows 6.7.0–6.7.6 and UFS storage is in use (check with `lsmod | grep ufs`), your system is vulnerable. Then run `sudo apt update && sudo apt install --only-upgrade linux-image-generic` (Ubuntu) or equivalent for your distro.

Does Defensia detect CVE-2024-26842?

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-2024-26842 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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