medium CVSS 5.5

CVE-2024-38553·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: net: fec: remove .ndo_poll_controller to avoid deadlocks There is a deadlock issue found in sungem driver, please refer to the commit ac0a230f719b ("eth: sungem: remove .ndo_poll_controller to avoid deadlocks"). The root cause of the issue is that netpoll is in atomic context and disable_irq() is called by .ndo_poll_controller interface of sungem driver, however, disable_irq() might sleep. After analyzing the implementation of fec_poll_controller(), the fec driver should have the same issue. Due to the fec driver uses NAPI for TX completions, the .ndo_poll_controller is unnecessary to be implemented in the fec driver, so fec_poll_controller() can be safely removed.

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 a deadlock vulnerability in the FEC network driver. The vulnerability stems from the ndo_poll_controller interface calling disable_irq() within atomic netpoll context, which can cause the system to hang. Kernel versions 6.9 through 6.9.2 are affected; upgrading removes the problematic polling controller implementation entirely since the driver relies on NAPI for packet completions.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Check installed kernel version: uname -r — if output shows 6.9.0, 6.9.1, or 6.9.2, your system is vulnerable.
  2. Verify FEC driver is in use: grep -i 'fec' /proc/net/dev or ethtool -i <interface> | grep driver — if FEC is the driver, the vulnerability applies.
  3. Search system logs for netpoll deadlock indicators: grep -i 'BUG: soft lockup' /var/log/kern.log or journalctl | grep 'lockup' — look for patterns occurring during network activity.
  4. Confirm fix is applied: uname -r should show 6.9.3 or later, and verify with: grep 'fec_poll_controller' /proc/config.gz — the function should not appear in the running kernel configuration.

FAQ

What is CVE-2024-38553?

CVE-2024-38553 is a kernel deadlock vulnerability in the Freescale Ethernet Controller (FEC) driver caused by the ndo_poll_controller interface invoking disable_irq() while running in netpoll's atomic context, potentially freezing the system during network polling operations.

Is CVE-2024-38553 being actively exploited?

No, this vulnerability is not listed in the CISA KEV catalog and no public exploits are available. However, it can be triggered through normal network activity on affected systems, causing availability disruption.

What versions of Kernel are affected by CVE-2024-38553?

Linux kernel versions 6.9.0, 6.9.1, and 6.9.2 are affected. The vulnerability was resolved in version 6.9.3 and later.

How do I check if my server is vulnerable to CVE-2024-38553?

Run 'uname -r' and check if the output is 6.9.0, 6.9.1, or 6.9.2; then verify the FEC driver is active with 'grep fec /proc/net/dev'. If both conditions are true, your system is vulnerable.

Does Defensia detect CVE-2024-38553?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Kernel is installed on a monitored server, CVE-2024-38553 will appear in your dashboard with remediation steps.

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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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