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CVE-2025-71070— ublk: clean up user copy references on ublk server exit

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ublk服务器退出时未清理用户复制引用，可能导致释放后重用。

CVSS 7.8 · High EPSS 0.14% · P3

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux e63d2228ef831af36f963b3ab8604160cfff84c1< 13456b4f1033d911f8bf3a0a1195656f293ba0f6 affected
e63d2228ef831af36f963b3ab8604160cfff84c1< daa24603d9f0808929514ee62ced30052ca7221c affected
e537193fc4a43b48ac51cc6366319e15e32dd540 affected
6.14.6< 6.15 affected
6.15 affected
< 6.15 unaffected
6.18.3≤ 6.18.* unaffected
6.19≤ * unaffected
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I. Basic Information for CVE-2025-71070

Vulnerability Information
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Vulnerability Title
ublk: clean up user copy references on ublk server exit
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ublk: clean up user copy references on ublk server exit If a ublk server process releases a ublk char device file, any requests dispatched to the ublk server but not yet completed will retain a ref value of UBLK_REFCOUNT_INIT. Before commit e63d2228ef83 ("ublk: simplify aborting ublk request"), __ublk_fail_req() would decrement the reference count before completing the failed request. However, that commit optimized __ublk_fail_req() to call __ublk_complete_rq() directly without decrementing the request reference count. The leaked reference count incorrectly allows user copy and zero copy operations on the completed ublk request. It also triggers the WARN_ON_ONCE(refcount_read(&io->ref)) warnings in ublk_queue_reinit() and ublk_deinit_queue(). Commit c5c5eb24ed61 ("ublk: avoid ublk_io_release() called after ublk char dev is closed") already fixed the issue for ublk devices using UBLK_F_SUPPORT_ZERO_COPY or UBLK_F_AUTO_BUF_REG. However, the reference count leak also affects UBLK_F_USER_COPY, the other reference-counted data copy mode. Fix the condition in ublk_check_and_reset_active_ref() to include all reference-counted data copy modes. This ensures that any ublk requests still owned by the ublk server when it exits have their reference counts reset to 0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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ublk服务器退出时未清理用户复制引用，可能导致释放后重用。
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 e63d2228ef831af36f963b3ab8604160cfff84c1 ~ 13456b4f1033d911f8bf3a0a1195656f293ba0f6 -
Linux Linux 6.15 -

II. Public POCs for CVE-2025-71070

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III. Intelligence Information for CVE-2025-71070

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Same Patch Batch · Linux · 2026-01-13 · 93 CVEs total

CVE-2025-68811 9.8 CRITICAL svcrdma: use rc_pageoff for memcpy byte offset
CVE-2025-68794 9.8 CRITICAL iomap: adjust read range correctly for non-block-aligned positions
CVE-2025-68817 9.8 CRITICAL ksmbd: fix use-after-free in ksmbd_tree_connect_put under concurrency
CVE-2025-68775 9.8 CRITICAL net/handshake: duplicate handshake cancellations leak socket
CVE-2025-71068 9.8 CRITICAL svcrdma: bound check rq_pages index in inline path
CVE-2025-68809 9.1 CRITICAL ksmbd: vfs: fix race on m_flags in vfs_cache
CVE-2025-71095 9.1 CRITICAL net: stmmac: fix the crash issue for zero copy XDP_TX action
CVE-2025-71093 9.1 CRITICAL e1000: fix OOB in e1000_tbi_should_accept()
CVE-2025-68818 8.8 HIGH scsi: Revert "scsi: qla2xxx: Perform lockless command completion in abort path"
CVE-2025-71072 8.2 HIGH shmem: fix recovery on rename failures
CVE-2025-68799 8.1 HIGH caif: fix integer underflow in cffrml_receive()
CVE-2025-68803 8.0 HIGH NFSD: NFSv4 file creation neglects setting ACL
CVE-2025-68808 7.8 HIGH media: vidtv: initialize local pointers upon transfer of memory ownership
CVE-2025-68819 7.8 HIGH media: dvb-usb: dtv5100: fix out-of-bounds in dtv5100_i2c_msg()
CVE-2025-71092 7.8 HIGH RDMA/bnxt_re: Fix OOB write in bnxt_re_copy_err_stats()
CVE-2025-68792 7.8 HIGH tpm2-sessions: Fix out of range indexing in name_size
CVE-2025-68793 7.8 HIGH drm/amdgpu: fix a job->pasid access race in gpu recovery
CVE-2025-71099 7.8 HIGH drm/xe/oa: Fix potential UAF in xe_oa_add_config_ioctl()
CVE-2025-68805 7.8 HIGH fuse: fix io-uring list corruption for terminated non-committed requests
CVE-2025-68795 7.8 HIGH ethtool: Avoid overflowing userspace buffer on stats query

Showing top 20 of 93 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2025-71070

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