medium CVSS 5.5

CVE-2023-52817·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Fix a null pointer access when the smc_rreg pointer is NULL In certain types of chips, such as VEGA20, reading the amdgpu_regs_smc file could result in an abnormal null pointer access when the smc_rreg pointer is NULL. Below are the steps to reproduce this issue and the corresponding exception log: 1. Navigate to the directory: /sys/kernel/debug/dri/0 2. Execute command: cat amdgpu_regs_smc 3. Exception Log:: [4005007.702554] BUG: kernel NULL pointer dereference, address: 0000000000000000 [4005007.702562] #PF: supervisor instruction fetch in kernel mode [4005007.702567] #PF: error_code(0x0010) - not-present page [4005007.702570] PGD 0 P4D 0 [4005007.702576] Oops: 0010 [#1] SMP NOPTI [4005007.702581] CPU: 4 PID: 62563 Comm: cat Tainted: G OE 5.15.0-43-generic #46-Ubunt u [4005007.702590] RIP: 0010:0x0 [4005007.702598] Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. [4005007.702600] RSP: 0018:ffffa82b46d27da0 EFLAGS: 00010206 [4005007.702605] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffa82b46d27e68 [4005007.702609] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff9940656e0000 [4005007.702612] RBP: ffffa82b46d27dd8 R08: 0000000000000000 R09: ffff994060c07980 [4005007.702615] R10: 0000000000020000 R11: 0000000000000000 R12: 00007f5e06753000 [4005007.702618] R13: ffff9940656e0000 R14: ffffa82b46d27e68 R15: 00007f5e06753000 [4005007.702622] FS: 00007f5e0755b740(0000) GS:ffff99479d300000(0000) knlGS:0000000000000000 [4005007.702626] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [4005007.702629] CR2: ffffffffffffffd6 CR3: 00000003253fc000 CR4: 00000000003506e0 [4005007.702633] Call Trace: [4005007.702636] <TASK> [4005007.702640] amdgpu_debugfs_regs_smc_read+0xb0/0x120 [amdgpu] [4005007.703002] full_proxy_read+0x5c/0x80 [4005007.703011] vfs_read+0x9f/0x1a0 [4005007.703019] ksys_read+0x67/0xe0 [4005007.703023] __x64_sys_read+0x19/0x20 [4005007.703028] do_syscall_64+0x5c/0xc0 [4005007.703034] ? do_user_addr_fault+0x1e3/0x670 [4005007.703040] ? exit_to_user_mode_prepare+0x37/0xb0 [4005007.703047] ? irqentry_exit_to_user_mode+0x9/0x20 [4005007.703052] ? irqentry_exit+0x19/0x30 [4005007.703057] ? exc_page_fault+0x89/0x160 [4005007.703062] ? asm_exc_page_fault+0x8/0x30 [4005007.703068] entry_SYSCALL_64_after_hwframe+0x44/0xae [4005007.703075] RIP: 0033:0x7f5e07672992 [4005007.703079] Code: c0 e9 b2 fe ff ff 50 48 8d 3d fa b2 0c 00 e8 c5 1d 02 00 0f 1f 44 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 0f 05 <48> 3d 00 f0 ff ff 77 56 c3 0f 1f 44 00 00 48 83 e c 28 48 89 54 24 [4005007.703083] RSP: 002b:00007ffe03097898 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [4005007.703088] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f5e07672992 [4005007.703091] RDX: 0000000000020000 RSI: 00007f5e06753000 RDI: 0000000000000003 [4005007.703094] RBP: 00007f5e06753000 R08: 00007f5e06752010 R09: 00007f5e06752010 [4005007.703096] R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000022000 [4005007.703099] R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000 [4005007.703105] </TASK> [4005007.703107] Modules linked in: nf_tables libcrc32c nfnetlink algif_hash af_alg binfmt_misc nls_ iso8859_1 ipmi_ssif ast intel_rapl_msr intel_rapl_common drm_vram_helper drm_ttm_helper amd64_edac t tm edac_mce_amd kvm_amd ccp mac_hid k10temp kvm acpi_ipmi ipmi_si rapl sch_fq_codel ipmi_devintf ipm i_msghandler msr parport_pc ppdev lp parport mtd pstore_blk efi_pstore ramoops pstore_zone reed_solo mon ip_tables x_tables autofs4 ib_uverbs ib_core amdgpu(OE) amddrm_ttm_helper(OE) amdttm(OE) iommu_v 2 amd_sched(OE) amdkcl(OE) drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops cec rc_core drm igb ahci xhci_pci libahci i2c_piix4 i2c_algo_bit xhci_pci_renesas dca [4005007.703184] CR2: 0000000000000000 [4005007.703188] ---[ en ---truncated---

Severity
medium
Software
Kernel
Fixed in
6.6.3
Published
2024-05-21

Affected versions

From: 6.6

Until: 6.6.3

Fixed in: 6.6.3

How to fix this CVE

Update your Linux kernel to version 6.6.3 or later to resolve this null pointer dereference vulnerability affecting AMD GPU driver debugging functionality. The issue occurs when reading SMC (System Management Controller) registers on certain VEGA20 chips, causing a kernel crash. Apply the patch by updating your kernel package through your distribution's package manager.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Run `uname -r` to check your current kernel version; vulnerable versions are 6.6.0 through 6.6.2
  2. Check if AMD GPU drivers are loaded with `lsmod | grep amdgpu`; if not present, this system is not affected
  3. Review kernel logs for null pointer dereference errors with `dmesg | grep -i 'amdgpu_debugfs_regs_smc_read'` or `dmesg | grep -i 'null pointer'`
  4. Verify the fix by confirming kernel version is 6.6.3+ with `uname -r`, then attempt to safely read the SMC register file with `cat /sys/kernel/debug/dri/0/amdgpu_regs_smc` without kernel crashes

FAQ

What is CVE-2023-52817?

This vulnerability is a null pointer dereference in the AMD GPU driver's debugfs interface that occurs when the SMC (System Management Controller) register read function pointer is uninitialized on certain VEGA20 GPU chips, allowing local users to crash the kernel by accessing a debug file.

Is CVE-2023-52817 being actively exploited?

No, this vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog and no public exploits are currently available. However, any local user with access to debugfs can trigger a denial-of-service condition.

What versions of Kernel are affected by CVE-2023-52817?

Linux kernel versions 6.6.0 through 6.6.2 are affected. The vulnerability is fixed in kernel 6.6.3 and later.

How do I check if my server is vulnerable to CVE-2023-52817?

Run `uname -r` to check your kernel version. If it shows 6.6.0, 6.6.1, or 6.6.2 AND you have AMD GPU support enabled (check with `lsmod | grep amdgpu`), your system is vulnerable.

Does Defensia detect CVE-2023-52817?

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-2023-52817 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().
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-2026-64000CVSS 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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