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CVE-2025-21852— net: Add rx_skb of kfree_skb to raw_tp_null_args[].

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于未检查rx_sk空值，可能导致空指针取消引用。

AI Predicted 7.8 Difficulty: Moderate EPSS 0.22% · P11

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux c53795d48ee8f385c6a9e394651e7ee914baaeba< f579afacd0a66971fc8481f30d2d377e230a8342 affected
c53795d48ee8f385c6a9e394651e7ee914baaeba< 4dba79c1e7aad6620bbb707b6c4459380fd90860 affected
c53795d48ee8f385c6a9e394651e7ee914baaeba< 5da7e15fb5a12e78de974d8908f348e279922ce9 affected
6.11 affected
< 6.11 unaffected
6.12.17≤ 6.12.* unaffected
6.13.5≤ 6.13.* unaffected
6.14≤ * unaffected
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I. Basic Information for CVE-2025-21852

Vulnerability Information
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Vulnerability Title
net: Add rx_skb of kfree_skb to raw_tp_null_args[].
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: net: Add rx_skb of kfree_skb to raw_tp_null_args[]. Yan Zhai reported a BPF prog could trigger a null-ptr-deref [0] in trace_kfree_skb if the prog does not check if rx_sk is NULL. Commit c53795d48ee8 ("net: add rx_sk to trace_kfree_skb") added rx_sk to trace_kfree_skb, but rx_sk is optional and could be NULL. Let's add kfree_skb to raw_tp_null_args[] to let the BPF verifier validate such a prog and prevent the issue. Now we fail to load such a prog: libbpf: prog 'drop': -- BEGIN PROG LOAD LOG -- 0: R1=ctx() R10=fp0 ; int BPF_PROG(drop, struct sk_buff *skb, void *location, @ kfree_skb_sk_null.bpf.c:21 0: (79) r3 = *(u64 *)(r1 +24) func 'kfree_skb' arg3 has btf_id 5253 type STRUCT 'sock' 1: R1=ctx() R3_w=trusted_ptr_or_null_sock(id=1) ; bpf_printk("sk: %d, %d\n", sk, sk->__sk_common.skc_family); @ kfree_skb_sk_null.bpf.c:24 1: (69) r4 = *(u16 *)(r3 +16) R3 invalid mem access 'trusted_ptr_or_null_' processed 2 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0 -- END PROG LOAD LOG -- Note this fix requires commit 838a10bd2ebf ("bpf: Augment raw_tp arguments with PTR_MAYBE_NULL"). [0]: BUG: kernel NULL pointer dereference, address: 0000000000000010 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 0 P4D 0 PREEMPT SMP RIP: 0010:bpf_prog_5e21a6db8fcff1aa_drop+0x10/0x2d Call Trace: <TASK> ? __die+0x1f/0x60 ? page_fault_oops+0x148/0x420 ? search_bpf_extables+0x5b/0x70 ? fixup_exception+0x27/0x2c0 ? exc_page_fault+0x75/0x170 ? asm_exc_page_fault+0x22/0x30 ? bpf_prog_5e21a6db8fcff1aa_drop+0x10/0x2d bpf_trace_run4+0x68/0xd0 ? unix_stream_connect+0x1f4/0x6f0 sk_skb_reason_drop+0x90/0x120 unix_stream_connect+0x1f4/0x6f0 __sys_connect+0x7f/0xb0 __x64_sys_connect+0x14/0x20 do_syscall_64+0x47/0xc30 entry_SYSCALL_64_after_hwframe+0x4b/0x53
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于未检查rx_sk空值，可能导致空指针取消引用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux c53795d48ee8f385c6a9e394651e7ee914baaeba ~ f579afacd0a66971fc8481f30d2d377e230a8342 -
Linux Linux 6.11 -

II. Public POCs for CVE-2025-21852

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III. Intelligence Information for CVE-2025-21852

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Other References for CVE-2025-21852 (3)

Same Patch Batch · Linux · 2025-03-12 · 26 CVEs total

CVE-2024-58087 9.8 CRITICAL ksmbd: fix racy issue from session lookup and expire
CVE-2025-21850 9.8 CRITICAL nvmet: Fix crash when a namespace is disabled
CVE-2025-21855 8.6 HIGH ibmvnic: Don't reference skb after sending to VIOS
CVE-2024-58089 7.8 HIGH btrfs: fix double accounting race when btrfs_run_delalloc_range() failed
CVE-2025-21858 7.8 HIGH geneve: Fix use-after-free in geneve_find_dev().
CVE-2025-21864 7.8 HIGH tcp: drop secpath at the same time as we currently drop dst
CVE-2025-21851 7.8 HIGH bpf: Fix softlockup in arena_map_free on 64k page kernel
CVE-2025-21844 7.5 HIGH smb: client: Add check for next_buffer in receive_encrypted_standard()
CVE-2025-21863 io_uring: prevent opcode speculation
CVE-2025-21865 gtp: Suppress list corruption splat in gtp_net_exit_batch_rtnl().
CVE-2024-58088 bpf: Fix deadlock when freeing cgroup storage
CVE-2025-21845 mtd: spi-nor: sst: Fix SST write failure
CVE-2025-21846 acct: perform last write from workqueue
CVE-2025-21848 nfp: bpf: Add check for nfp_app_ctrl_msg_alloc()
CVE-2025-21847 ASoC: SOF: stream-ipc: Check for cstream nullity in sof_ipc_msg_data()
CVE-2025-21849 drm/i915/gt: Use spin_lock_irqsave() in interruptible context
CVE-2025-21853 bpf: avoid holding freeze_mutex during mmap operation
CVE-2025-21866 powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC
CVE-2025-21854 sockmap, vsock: For connectible sockets allow only connected
CVE-2025-21856 s390/ism: add release function for struct device

Showing top 20 of 26 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux