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CVE-2025-21866— powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC

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，该漏洞源于未正确标记文本修补区域，可能导致越界访问。

AI Predicted 5.5 Difficulty: Hard EPSS 0.25% · P16

Possible ATT&CK Techniques 1 AI

T1059 · Command and Scripting Interpreter

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1< 97de5852058a299ba447cd9782fe96488d30108b affected
37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1< f8d4c5b653c1bc0df56e15658bbf64fc359adc4e affected
37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1< 6847b3e40bb963e57b61d1cc6fe84cb37b9d3d4c affected
37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1< c905a3053518212a1017e50bd2be3bee59305bb0 affected
37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1< 2d542f13d26344e3452eee77613026ce9b653065 affected
37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1< 8d06e9208184b2851fa79a3a39d6860320c8bdf8 affected
37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1< 2e6c80423f201405fd65254e52decd21663896f3 affected
37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1< d262a192d38e527faa5984629aabda2e0d1c4f54 affected
… +10 more rows
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I. Basic Information for CVE-2025-21866

Vulnerability Information
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Vulnerability Title
powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC Erhard reported the following KASAN hit while booting his PowerMac G4 with a KASAN-enabled kernel 6.13-rc6: BUG: KASAN: vmalloc-out-of-bounds in copy_to_kernel_nofault+0xd8/0x1c8 Write of size 8 at addr f1000000 by task chronyd/1293 CPU: 0 UID: 123 PID: 1293 Comm: chronyd Tainted: G W 6.13.0-rc6-PMacG4 #2 Tainted: [W]=WARN Hardware name: PowerMac3,6 7455 0x80010303 PowerMac Call Trace: [c2437590] [c1631a84] dump_stack_lvl+0x70/0x8c (unreliable) [c24375b0] [c0504998] print_report+0xdc/0x504 [c2437610] [c050475c] kasan_report+0xf8/0x108 [c2437690] [c0505a3c] kasan_check_range+0x24/0x18c [c24376a0] [c03fb5e4] copy_to_kernel_nofault+0xd8/0x1c8 [c24376c0] [c004c014] patch_instructions+0x15c/0x16c [c2437710] [c00731a8] bpf_arch_text_copy+0x60/0x7c [c2437730] [c0281168] bpf_jit_binary_pack_finalize+0x50/0xac [c2437750] [c0073cf4] bpf_int_jit_compile+0xb30/0xdec [c2437880] [c0280394] bpf_prog_select_runtime+0x15c/0x478 [c24378d0] [c1263428] bpf_prepare_filter+0xbf8/0xc14 [c2437990] [c12677ec] bpf_prog_create_from_user+0x258/0x2b4 [c24379d0] [c027111c] do_seccomp+0x3dc/0x1890 [c2437ac0] [c001d8e0] system_call_exception+0x2dc/0x420 [c2437f30] [c00281ac] ret_from_syscall+0x0/0x2c --- interrupt: c00 at 0x5a1274 NIP: 005a1274 LR: 006a3b3c CTR: 005296c8 REGS: c2437f40 TRAP: 0c00 Tainted: G W (6.13.0-rc6-PMacG4) MSR: 0200f932 <VEC,EE,PR,FP,ME,IR,DR,RI> CR: 24004422 XER: 00000000 GPR00: 00000166 af8f3fa0 a7ee3540 00000001 00000000 013b6500 005a5858 0200f932 GPR08: 00000000 00001fe9 013d5fc8 005296c8 2822244c 00b2fcd8 00000000 af8f4b57 GPR16: 00000000 00000001 00000000 00000000 00000000 00000001 00000000 00000002 GPR24: 00afdbb0 00000000 00000000 00000000 006e0004 013ce060 006e7c1c 00000001 NIP [005a1274] 0x5a1274 LR [006a3b3c] 0x6a3b3c --- interrupt: c00 The buggy address belongs to the virtual mapping at [f1000000, f1002000) created by: text_area_cpu_up+0x20/0x190 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x76e30 flags: 0x80000000(zone=2) raw: 80000000 00000000 00000122 00000000 00000000 00000000 ffffffff 00000001 raw: 00000000 page dumped because: kasan: bad access detected Memory state around the buggy address: f0ffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f0ffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >f1000000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ f1000080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f1000100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== f8 corresponds to KASAN_VMALLOC_INVALID which means the area is not initialised hence not supposed to be used yet. Powerpc text patching infrastructure allocates a virtual memory area using get_vm_area() and flags it as VM_ALLOC. But that flag is meant to be used for vmalloc() and vmalloc() allocated memory is not supposed to be used before a call to __vmalloc_node_range() which is never called for that area. That went undetected until commit e4137f08816b ("mm, kasan, kmsan: instrument copy_from/to_kernel_nofault") The area allocated by text_area_cpu_up() is not vmalloc memory, it is mapped directly on demand when needed by map_kernel_page(). There is no VM flag corresponding to such usage, so just pass no flag. That way the area will be unpoisonned and usable immediately.
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，该漏洞源于未正确标记文本修补区域，可能导致越界访问。
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 37bc3e5fd764fb258ff4fcbb90b6d1b67fb466c1 ~ 97de5852058a299ba447cd9782fe96488d30108b -
Linux Linux 4.13 -

II. Public POCs for CVE-2025-21866

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III. Intelligence Information for CVE-2025-21866

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Other References for CVE-2025-21866 (8)

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-2025-21864 7.8 HIGH tcp: drop secpath at the same time as we currently drop dst
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-2025-21851 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-2025-21853 bpf: avoid holding freeze_mutex during mmap operation
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-2025-21852 net: Add rx_skb of kfree_skb to raw_tp_null_args[].
CVE-2025-21865 gtp: Suppress list corruption splat in gtp_net_exit_batch_rtnl().
CVE-2025-21854 sockmap, vsock: For connectible sockets allow only connected
CVE-2025-21856 s390/ism: add release function for struct device
CVE-2025-21857 net/sched: cls_api: fix error handling causing NULL dereference

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

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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