medium CVSS 5.5

CVE-2024-36930·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: spi: fix null pointer dereference within spi_sync If spi_sync() is called with the non-empty queue and the same spi_message is then reused, the complete callback for the message remains set while the context is cleared, leading to a null pointer dereference when the callback is invoked from spi_finalize_current_message(). With function inlining disabled, the call stack might look like this: _raw_spin_lock_irqsave from complete_with_flags+0x18/0x58 complete_with_flags from spi_complete+0x8/0xc spi_complete from spi_finalize_current_message+0xec/0x184 spi_finalize_current_message from spi_transfer_one_message+0x2a8/0x474 spi_transfer_one_message from __spi_pump_transfer_message+0x104/0x230 __spi_pump_transfer_message from __spi_transfer_message_noqueue+0x30/0xc4 __spi_transfer_message_noqueue from __spi_sync+0x204/0x248 __spi_sync from spi_sync+0x24/0x3c spi_sync from mcp251xfd_regmap_crc_read+0x124/0x28c [mcp251xfd] mcp251xfd_regmap_crc_read [mcp251xfd] from _regmap_raw_read+0xf8/0x154 _regmap_raw_read from _regmap_bus_read+0x44/0x70 _regmap_bus_read from _regmap_read+0x60/0xd8 _regmap_read from regmap_read+0x3c/0x5c regmap_read from mcp251xfd_alloc_can_err_skb+0x1c/0x54 [mcp251xfd] mcp251xfd_alloc_can_err_skb [mcp251xfd] from mcp251xfd_irq+0x194/0xe70 [mcp251xfd] mcp251xfd_irq [mcp251xfd] from irq_thread_fn+0x1c/0x78 irq_thread_fn from irq_thread+0x118/0x1f4 irq_thread from kthread+0xd8/0xf4 kthread from ret_from_fork+0x14/0x28 Fix this by also setting message->complete to NULL when the transfer is complete.

Severity: medium
Software: Kernel
Fixed in: 6.8.10
Published: 2024-05-30

Affected versions

From: 6.7

Until: 6.8.10

Fixed in: 6.8.10

How to fix this CVE

Update your Linux kernel to version 6.8.10 or later to resolve a null pointer dereference in the SPI subsystem that occurs when reusing SPI messages. This flaw can cause kernel crashes under specific SPI transfer patterns, particularly affecting CAN bus drivers and other SPI-dependent hardware. Apply the patch immediately to maintain system stability and prevent unexpected downtime.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

Run `uname -r` to check the current kernel version; vulnerable versions are 6.7.x through 6.8.9
Check if SPI devices are in use: `lsmod | grep spi` — look for spi_core, mcp251xfd, or similar SPI driver modules
Search kernel logs for SPI-related crashes: `dmesg | grep -i 'spi\|null pointer\|oops'` or `journalctl -b | grep -i spi`
Verify the patch is installed by confirming kernel version is 6.8.10 or later with `uname -r`

FAQ

What is CVE-2024-36930?

This vulnerability is a null pointer dereference in the Linux kernel's SPI (Serial Peripheral Interface) subsystem that occurs when an SPI message is reused while still queued, causing the completion callback to reference cleared context data and triggering a kernel crash.

Is CVE-2024-36930 being actively exploited?

No, this vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog and no public exploits are available. Exploitation requires local access and specific SPI driver conditions.

What versions of Kernel are affected by CVE-2024-36930?

Linux kernel versions 6.7.0 through 6.8.9 are affected. Kernel 6.8.10 and later contain the fix.

How do I check if my server is vulnerable to CVE-2024-36930?

Run `uname -r` and compare the output to the affected range (6.7.x to 6.8.9). If your version falls within this range and SPI devices are active, your system is vulnerable.

Does Defensia detect CVE-2024-36930?

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-2024-36930 will appear in your dashboard with remediation steps.

Related Kernel CVEs

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CVE-2026-64025CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: bpf, skmsg: fix verdict sk_data_ready racing with ktls rx sk_psock_strp_data_ready() already checks tls_sw_has_ctx_rx() and defers to psock->saved_data_ready when a TLS RX context is present, avoiding a conflict with the TLS strparser's ownership of the receive queue (commit e91de6afa81c, "bpf: Fix running sk_skb program types with ktls"). sk_psock_verdict_data_ready() has no equivalent guard. When a socket is inserted into a sockmap (BPF_SK_SKB_VERDICT) before TLS RX is configured, tls_sw_strparser_arm() saves sk_psock_verdict_data_ready as rx_ctx->saved_data_ready. On data arrival: tls_data_ready -> tls_strp_data_ready -> tls_rx_msg_ready -> saved_data_ready() = sk_psock_verdict_data_ready() -> tcp_read_skb() drains sk_receive_queue via __skb_unlink() without calling tcp_eat_skb(), so copied_seq is not advanced. tls_strp_msg_load() then finds tcp_inq() >= full_len (stale), calls tcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and returns with rx_ctx->strp.anchor.frag_list pointing at a psock-owned (potentially freed) skb. tls_decrypt_sg() subsequently walks that frag_list: use-after-free. Apply the same fix as sk_psock_strp_data_ready(): if a TLS RX context is present, call psock->saved_data_ready (sock_def_readable) to wake recv() waiters and return immediately, leaving the receive queue untouched. TLS retains sole ownership of the queue and decrypts the record normally through tls_sw_recvmsg().

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CVE-2026-64000CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: net: hsr: fix potential OOB access in supervision frame handling Ensure the entire TLV header is linearized before access by adding sizeof(struct hsr_sup_tlv) to the pskb_may_pull() calls. Without this, a truncated frame could cause an out-of-bounds access.

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.

References

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