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CVE-2026-80970— ALSA: FCP: do not copy out an uninitialised init response

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基金会开源的一个操作系统内核。 Linux kernel 6.14版本存在安全漏洞，该漏洞源于ALSA FCP驱动中的fcp_ioctl_init()函数未初始化由kmalloc分配的响应缓冲区，且未正确处理短控制传输，导致未初始化的内核内存被复制到用户空间，造成信息泄露。

AI Predicted 5.5 Difficulty: Easy EPSS 0.21% · P10

Possible ATT&CK Techniques 1 AI

T1507

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux 46757a3e7d50dac923888e7fbe68377736f13c70< e9e52437120fb5f802152877ba20c4b406c9fa9e affected
46757a3e7d50dac923888e7fbe68377736f13c70< 29ab2df278ab4f1d238cd9c1c393ee00db175cba affected
46757a3e7d50dac923888e7fbe68377736f13c70< 4335e387786479889e6db691fe06d345e52ea536 affected
6.14 affected
< 6.14 unaffected
6.18.52≤ 6.18.* unaffected
7.2.4≤ 7.2.* unaffected
7.3-rc1≤ * unaffected
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I. Basic Information for CVE-2026-80970

Vulnerability Information
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Vulnerability Title
ALSA: FCP: do not copy out an uninitialised init response
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: FCP: do not copy out an uninitialised init response fcp_ioctl_init() allocates its response buffer with kmalloc() and copies the whole buffer back to userspace: buf_size = init.step0_resp_size + init.step2_resp_size; void *resp __free(kfree) = kmalloc(buf_size, GFP_KERNEL); ... if (copy_to_user(arg->resp, resp, buf_size)) return -EFAULT; Nothing clears the buffer, and the only writer of its leading step0_resp_size bytes is the step-0 control transfer: err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), FCP_USB_REQ_STEP0, USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN, 0, private->bInterfaceNumber, step0_resp, private->step0_resp_size); if (err < 0) return err; usb_fill_control_urb() does not set URB_SHORT_NOT_OK, so a short or zero-length data stage completes with status 0 and snd_usb_ctl_msg() returns a small actual_length. The only check is err < 0, so a short transfer is accepted as success. snd_usb_ctl_msg() copies the full size back unconditionally: buf = kmemdup(data, size, GFP_KERNEL); ... memcpy(data, buf, size); Bytes the device never wrote are therefore restored into resp unchanged and copied to userspace. step0_resp_size and step2_resp_size are each validated only to 1..255, so the caller also picks the slab cache, from kmalloc-8 up to kmalloc-512. On 7.2.0-rc5 (arm64), device answering step 0 with a zero-length data stage, s0 = s2 = 255: # init_on_alloc off, no spray step0 window [0,255): nonzero=94/255 000: 00 80 60 06 00 00 ff ff 18 00 00 00 57 01 ea 01 010: 08 78 22 13 00 00 ff ff a8 c4 5f 80 00 80 ff ff # same kernel, kmalloc-512 pre-seeded with an 8-byte tag step0 window [0,255): nonzero=219/255 tagbytes=232 # identical run, init_on_alloc=1 step0 window [0,255): nonzero=0/255 tagbytes=0 # all three runs step2 window [255,510): device words matched=62/62 a8 c4 5f 80 00 80 ff ff is the little-endian kernel text address ffff8000805fc4a8. The step-2 window is unaffected, so the disclosure is exactly the step-0 region. Zero the buffer, and require the step-0 transfer to deliver the full step0_resp_size bytes so a short data stage is reported as an error. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>
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基金会开源的一个操作系统内核。 Linux kernel 6.14版本存在安全漏洞，该漏洞源于ALSA FCP驱动中的fcp_ioctl_init()函数未初始化由kmalloc分配的响应缓冲区，且未正确处理短控制传输，导致未初始化的内核内存被复制到用户空间，造成信息泄露。
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 46757a3e7d50dac923888e7fbe68377736f13c70 ~ e9e52437120fb5f802152877ba20c4b406c9fa9e -
Linux Linux 6.14 -

II. Public POCs for CVE-2026-80970

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III. Intelligence Information for CVE-2026-80970

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Patches & Fixes for CVE-2026-80970 (3)

Same Patch Batch · Linux · 2026-09-11 · 431 CVEs total

CVE-2026-89688 9.8 CRITICAL nfsd: drop the stateid, not the stateowner, on seqid_op replay retry
CVE-2026-89656 9.8 CRITICAL libceph: reject buckets with mismatched CRUSH ids
CVE-2026-89655 9.8 CRITICAL ceph: fix UAF in __kick_flushing_caps() on cf entry freed during unlock
CVE-2026-89658 9.8 CRITICAL NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup
CVE-2026-89660 9.8 CRITICAL NFSD: Prevent client use-after-free during admin state revocation
CVE-2026-89659 9.8 CRITICAL NFSD: Prevent client use-after-free during delegation revoke
CVE-2026-89662 9.8 CRITICAL NFSD: Prevent lock owner use-after-free during client teardown
CVE-2026-89669 9.8 CRITICAL nfsd: initialize copy-notify stateid before publishing it
CVE-2026-89674 9.8 CRITICAL nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget
CVE-2026-89675 9.8 CRITICAL nfsd: fix UAF in async copy cancel and shutdown
CVE-2026-89676 9.8 CRITICAL nfsd: fix stale s2s_cp_stateids IDR entry for async COPY
CVE-2026-89677 9.8 CRITICAL nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()
CVE-2026-89681 9.8 CRITICAL nfsd: fix layout fence worker double-reference race
CVE-2026-89686 9.8 CRITICAL nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke
CVE-2026-89703 9.8 CRITICAL nfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations
CVE-2026-89479 9.8 CRITICAL sctp: stop processing a packet once its association is deleted
CVE-2026-89478 9.8 CRITICAL sctp: drop a chunk if its transport was removed
CVE-2026-89702 9.8 CRITICAL nfsd: size fh_verify server sockaddr slot by xpt_locallen
CVE-2026-89482 9.8 CRITICAL nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
CVE-2026-89708 9.8 CRITICAL nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown

Showing top 20 of 431 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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