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CVE-2025-39686— comedi: Make insn_rw_emulate_bits() do insn->n samples

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comedi模块insn_rw_emulate_bits函数未处理insn->n样本。

AI Predicted 5.5 Difficulty: Moderate EPSS 0.19% · P8

Possible ATT&CK Techniques 1 AI

T1059 · Command and Scripting Interpreter

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux ed9eccbe8970f6eedc1b978c157caf1251a896d4< ab77e85bd3bc006ef40738f26f446a660813da44 affected
ed9eccbe8970f6eedc1b978c157caf1251a896d4< ae8bc1f07bcb31b8636420e03d1f9c3df6219a2b affected
ed9eccbe8970f6eedc1b978c157caf1251a896d4< 842f307a1d115b24f2bcb2415c4e344f11f55930 affected
ed9eccbe8970f6eedc1b978c157caf1251a896d4< 92352ed2f9ac422181e381c2430c2d0dfb46faa0 affected
ed9eccbe8970f6eedc1b978c157caf1251a896d4< dc0a2f142d655700db43de90cb6abf141b73d908 affected
ed9eccbe8970f6eedc1b978c157caf1251a896d4< 7afba9221f70d4cbce0f417c558879cba0eb5e66 affected
2.6.29 affected
< 2.6.29 unaffected
… +6 more rows
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I. Basic Information for CVE-2025-39686

Vulnerability Information
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Vulnerability Title
comedi: Make insn_rw_emulate_bits() do insn->n samples
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: comedi: Make insn_rw_emulate_bits() do insn->n samples The `insn_rw_emulate_bits()` function is used as a default handler for `INSN_READ` instructions for subdevices that have a handler for `INSN_BITS` but not for `INSN_READ`. Similarly, it is used as a default handler for `INSN_WRITE` instructions for subdevices that have a handler for `INSN_BITS` but not for `INSN_WRITE`. It works by emulating the `INSN_READ` or `INSN_WRITE` instruction handling with a constructed `INSN_BITS` instruction. However, `INSN_READ` and `INSN_WRITE` instructions are supposed to be able read or write multiple samples, indicated by the `insn->n` value, but `insn_rw_emulate_bits()` currently only handles a single sample. For `INSN_READ`, the comedi core will copy `insn->n` samples back to user-space. (That triggered KASAN kernel-infoleak errors when `insn->n` was greater than 1, but that is being fixed more generally elsewhere in the comedi core.) Make `insn_rw_emulate_bits()` either handle `insn->n` samples, or return an error, to conform to the general expectation for `INSN_READ` and `INSN_WRITE` handlers.
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comedi模块insn_rw_emulate_bits函数未处理insn->n样本。
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 ed9eccbe8970f6eedc1b978c157caf1251a896d4 ~ ab77e85bd3bc006ef40738f26f446a660813da44 -
Linux Linux 2.6.29 -

II. Public POCs for CVE-2025-39686

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III. Intelligence Information for CVE-2025-39686

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Same Patch Batch · Linux · 2025-09-05 · 60 CVEs total

CVE-2025-39726 9.8 CRITICAL s390/ism: fix concurrency management in ism_cmd()
CVE-2025-39682 9.8 CRITICAL tls: fix handling of zero-length records on the rx_list
CVE-2025-38734 9.8 CRITICAL net/smc: fix UAF on smcsk after smc_listen_out()
CVE-2025-39702 9.8 CRITICAL ipv6: sr: Fix MAC comparison to be constant-time
CVE-2025-39703 9.8 CRITICAL net, hsr: reject HSR frame if skb can't hold tag
CVE-2025-38737 9.8 CRITICAL cifs: Fix oops due to uninitialised variable
CVE-2025-39673 9.8 CRITICAL ppp: fix race conditions in ppp_fill_forward_path
CVE-2025-39704 8.8 HIGH LoongArch: KVM: Fix stack protector issue in send_ipi_data()
CVE-2025-39718 8.4 HIGH vsock/virtio: Validate length in packet header before skb_put()
CVE-2025-39711 7.8 HIGH media: ivsc: Fix crash at shutdown due to missing mei_cldev_disable() calls
CVE-2025-39710 7.8 HIGH media: venus: Add a check for packet size after reading from shared memory
CVE-2025-39697 7.8 HIGH NFS: Fix a race when updating an existing write
CVE-2025-39714 7.8 HIGH media: usbtv: Lock resolution while streaming
CVE-2025-39717 7.8 HIGH open_tree_attr: do not allow id-mapping changes without OPEN_TREE_CLONE
CVE-2025-39698 7.8 HIGH io_uring/futex: ensure io_futex_wait() cleans up properly on failure
CVE-2025-38731 7.8 HIGH drm/xe: Fix vm_bind_ioctl double free bug
CVE-2025-39696 7.8 HIGH ALSA: hda: tas2781: Fix wrong reference of tasdevice_priv
CVE-2025-39691 7.8 HIGH fs/buffer: fix use-after-free when call bh_read() helper
CVE-2025-39689 7.8 HIGH ftrace: Also allocate and copy hash for reading of filter files
CVE-2025-39677 7.8 HIGH net/sched: Fix backlog accounting in qdisc_dequeue_internal

Showing top 20 of 60 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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