blk-cgroup: Fix class @block_class's subsystem refcount leakage
Priority LOW 24Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 5 fixed, 4 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: Fix class @block_class's subsystem refcount leakage blkcg_fill_root_iostats() iterates over @block_class's devices by class_dev_iter_(init|next)(), but does not end iterating with class_dev_iter_exit(), so causes the class's subsystem refcount leakage. Fix by ending the iterating with class_dev_iter_exit().
Why it matters now
EPSS 0.00266 18th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.235, 5.15.179, 6.1.129 +4Red Hat: 1 advisoryRed Hat: 5 fixed, 4 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.9 and later | 5.10.235, 5.15.179, 6.1.129, 6.6.78, 6.12.14, 6.13.3, 6.14 | Patch available | CNA |
- Linux VendorLinux Affected 5.9 and later Fixed in 5.10.235, 5.15.179, 6.1.129, 6.6.78, 6.12.14, 6.13.3, 6.14 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 5.9 to before 6.1.129; 6.2 to before 6.6.78; 6.7 to before 6.12.14; 6.13 to before 6.13.3 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.9 to before 6.1.129; 6.2 to before 6.6.78; 6.7 to before 6.12.14; 6.13 to before 6.13.3 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.235, 5.15.179, 6.1.129, 6.6.78, 6.12.14, 6.13.3, 6.14
Red Hat 1 advisory
- RHSA-2025:20518 Released 2025-11-11 · Red Hat rating Moderatekernel security update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-611.5.1.el9_7, kernel-64k-debug-devel-matched-5.14.0-611.5.1.el9_7, kernel-64k-devel-5.14.0-611.5.1.el9_7 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-611.5.1.el9_7, kernel-64k-5.14.0-611.5.1.el9_7, kernel-64k-core-5.14.0-611.5.1.el9_7 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-611.5.1.el9_7, libperf-5.14.0-611.5.1.el9_7
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-611.5.1.el9_7, kernel-rt-64k-5.14.0-611.5.1.el9_7, kernel-rt-64k-core-5.14.0-611.5.1.el9_7 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-611.5.1.el9_7, kernel-rt-core-5.14.0-611.5.1.el9_7, kernel-rt-debug-5.14.0-611.5.1.el9_7 +9
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2025:20518 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2025:20518 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2025:20518 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2025:20518 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2025:20518 |
Timeline
- 2026-10-02 Threatist record created from CVE-2025-21745
- 2026-10-03 Alias added: GHSA-hfgc-7c7c-g6r6
- 2026-10-29 Affected versions changed · Red Hat
References
Patch 5
- https://git.kernel.org/stable/c/431b6ef2714be4d5babb802114987541a88b43b0
- https://git.kernel.org/stable/c/993121481b5a87829f1e8163f47158b72679f309
- https://git.kernel.org/stable/c/2ce09aabe009453d641a2ceb79e6461a2d4f3876
- https://git.kernel.org/stable/c/67c7f213e052b1aa6caba4a7e25e303bc6997126
- https://git.kernel.org/stable/c/d1248436cbef1f924c04255367ff4845ccd9025e
More Linux Kernel vulnerabilities
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- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2025-21745 · CVE Program
- CVE-2025-21745 · NVD
- FIRST EPSS
- GHSA-hfgc-7c7c-g6r6 · GitHub Advisory Database · CC BY 4.0
- CVE-2025-21745 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences