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CVE-2025-71070VulnerabilityPublished Updated

CVE-2025-71070: Linux hwe edge · 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

Affects linux-hwe-edgeSource GCVE Database

0

Not known to be exploited · CVSS 7.8 Medium · fixed in 6.17.0-1018.18 : update linux-hwe-edge when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score
7.8Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.17.0-1018.18, 6.17.0-1013.13~24.04.1, 6.17.0-1012.12~24.04.1 +1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Jan 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

Upgrade linux-hwe-edge to 6.17.0-1018.18, 6.17.0-1013.13~24.04.1, 6.17.0-1012.12~24.04.1 or 6.17.0-22.22~24.04.1.

Affected software

ProductAffectedFixed in
linux-hwe-edgeAffected
  • <6.17.0-1012.12~24.04.1
  • <6.17.0-1013.13~24.04.1
  • <6.17.0-22.22~24.04.1
  • <6.17.0-1018.18
Fixed in
  • 6.17.0-1012.12~24.04.1
  • 6.17.0-1013.13~24.04.1
  • 6.17.0-22.22~24.04.1
  • 6.17.0-1018.18

AI-suggested

A fix has been implemented in the Linux kernel to properly reset reference counts for all reference-counted ublk data copy modes when the ublk server exits. Users should apply the official kernel updates that include this fix. Since this is a kernel vulnerability, upgrading to a patched kernel version is the recommended remediation. Patch status is not explicitly confirmed here; check the vendor or kernel mailing list advisories for the exact fixed versions and update accordingly.

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.

References

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