nbd: defer config unlock in nbd_genl_connect
Key facts
- Attack vector
- —
- Privileges required
- —
- User interaction
- —
- Attack complexity
- —
- Impact type
- —
- Confidentiality · integrity · availability
- —
- Fix status
- Partial Red Hat: 39 fixed, 1 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: nbd: defer config unlock in nbd_genl_connect There is one use-after-free warning when running NBD_CMD_CONNECT and NBD_CLEAR_SOCK: nbd_genl_connect nbd_alloc_and_init_config // config_refs=1 nbd_start_device // config_refs=2 set NBD_RT_HAS_CONFIG_REF open nbd // config_refs=3 recv_work done // config_refs=2 NBD_CLEAR_SOCK // config_refs=1 close nbd // config_refs=0 refcount_inc -> uaf ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 24 PID: 1014 at lib/refcount.c:25 refcount_warn_saturate+0x12e/0x290 nbd_genl_connect+0x16d0/0x1ab0 genl_family_rcv_msg_doit+0x1f3/0x310 genl_rcv_msg+0x44a/0x790 The issue can be easily reproduced by adding a small delay before refcount_inc(&nbd->config_refs) in nbd_genl_connect(): mutex_unlock(&nbd->config_lock); if (!ret) { set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags); + printk("before sleep\n"); + mdelay(5 * 1000); + printk("after sleep\n"); refcount_inc(&nbd->config_refs); nbd_connect_reply(info, nbd->index); }
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 4.12 and later | 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.63, 6.17.13, 6.18.2, 6.19 | Patch available | CNA |
- Linux VendorLinux Affected 4.12 and later Fixed in 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.63, 6.17.13, 6.18.2, 6.19 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.63, 6.17.13, 6.18.2, 6.19
Red Hat 12 advisories
- RHSA-2026:26563 Released 2026-06-17 · Red Hat rating Importantkernel security update
- Red Hat Enterprise Linux BaseOS E4S (v.8.8) bpftool-4.18.0-477.147.1.el8_8, kernel-4.18.0-477.147.1.el8_8, kernel-abi-stablelists-4.18.0-477.147.1.el8_8 +14
- Red Hat Enterprise Linux BaseOS TUS (v.8.8) bpftool-4.18.0-477.147.1.el8_8, kernel-4.18.0-477.147.1.el8_8, kernel-abi-stablelists-4.18.0-477.147.1.el8_8 +14
- RHSA-2026:26535 Released 2026-06-17 · Red Hat rating Criticalkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS AUS (v.8.4) bpftool-4.18.0-305.194.1.el8_4, kernel-4.18.0-305.194.1.el8_4, kernel-abi-stablelists-4.18.0-305.194.1.el8_4 +14
- Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) bpftool-4.18.0-305.194.1.el8_4, kernel-4.18.0-305.194.1.el8_4, kernel-abi-stablelists-4.18.0-305.194.1.el8_4 +14
- RHSA-2026:26515 Released 2026-06-17 · Red Hat rating Importantkernel security update
- Red Hat Enterprise Linux AppStream E4S (v.9.2) kernel-64k-debug-devel-5.14.0-284.176.1.el9_2, kernel-64k-debug-devel-matched-5.14.0-284.176.1.el9_2, kernel-64k-devel-5.14.0-284.176.1.el9_2 +10
- Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool-7.0.0-284.176.1.el9_2, kernel-5.14.0-284.176.1.el9_2, kernel-64k-5.14.0-284.176.1.el9_2 +29
Show 9 more Red Hat advisories
- RHSA-2026:26462 Released 2026-06-17 · Red Hat rating Importantkernel-rt security update
- Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt-5.14.0-284.176.1.rt14.461.el9_2, kernel-rt-core-5.14.0-284.176.1.rt14.461.el9_2, kernel-rt-debug-5.14.0-284.176.1.rt14.461.el9_2 +9
- Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt-5.14.0-284.176.1.rt14.461.el9_2, kernel-rt-core-5.14.0-284.176.1.rt14.461.el9_2, kernel-rt-debug-5.14.0-284.176.1.rt14.461.el9_2 +11
- RHSA-2026:25533 Released 2026-06-12 · Red Hat rating Criticalkernel security update
- Red Hat Enterprise Linux BaseOS AUS (v.8.6) bpftool-4.18.0-372.195.1.el8_6, kernel-4.18.0-372.195.1.el8_6, kernel-abi-stablelists-4.18.0-372.195.1.el8_6 +14
- Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) bpftool-4.18.0-372.195.1.el8_6, kernel-4.18.0-372.195.1.el8_6, kernel-abi-stablelists-4.18.0-372.195.1.el8_6 +14
- RHSA-2026:25121 Released 2026-06-10 · Red Hat rating Criticalkernel security update
- Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.132.1.el8_10, kernel-4.18.0-553.132.1.el8_10, kernel-abi-stablelists-4.18.0-553.132.1.el8_10 +19
- Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.132.1.el8_10
- RHSA-2026:25120 Released 2026-06-10 · Red Hat rating Criticalkernel-rt security update
- Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.132.1.rt7.473.el8_10, kernel-rt-core-4.18.0-553.132.1.rt7.473.el8_10, kernel-rt-debug-4.18.0-553.132.1.rt7.473.el8_10 +9
- Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.132.1.rt7.473.el8_10, kernel-rt-core-4.18.0-553.132.1.rt7.473.el8_10, kernel-rt-debug-4.18.0-553.132.1.rt7.473.el8_10 +7
- RHSA-2026:24343 Released 2026-06-08 · Red Hat rating Importantkernel security update
- Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.77.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.77.1.el10_0, kernel-64k-devel-6.12.0-55.77.1.el10_0 +12
- Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.77.1.el10_0, kernel-64k-6.12.0-55.77.1.el10_0, kernel-64k-core-6.12.0-55.77.1.el10_0 +28
- Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.77.1.el10_0, libperf-6.12.0-55.77.1.el10_0
- Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.77.1.el10_0, kernel-rt-64k-6.12.0-55.77.1.el10_0, kernel-rt-64k-core-6.12.0-55.77.1.el10_0 +21
- Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.77.1.el10_0, kernel-rt-core-6.12.0-55.77.1.el10_0, kernel-rt-debug-6.12.0-55.77.1.el10_0 +11
- RHSA-2026:23329 Released 2026-06-04 · Red Hat rating Importantkernel security update
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.20.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.20.1.el10_2, kernel-64k-devel-6.12.0-211.20.1.el10_2 +12
- Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.20.1.el10_2, kernel-64k-6.12.0-211.20.1.el10_2, kernel-64k-core-6.12.0-211.20.1.el10_2 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.20.1.el10_2, libperf-6.12.0-211.20.1.el10_2
- Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.20.1.el10_2, kernel-rt-64k-6.12.0-211.20.1.el10_2, kernel-rt-64k-core-6.12.0-211.20.1.el10_2 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.20.1.el10_2, kernel-rt-core-6.12.0-211.20.1.el10_2, kernel-rt-debug-6.12.0-211.20.1.el10_2 +9
- RHSA-2026:23224 Released 2026-06-04 · Red Hat rating Importantkernel security update
- Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.119.1.el9_6, libperf-5.14.0-570.119.1.el9_6
- Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.119.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.119.1.el9_6, kernel-64k-devel-5.14.0-570.119.1.el9_6 +12
- Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.119.1.el9_6, kernel-64k-5.14.0-570.119.1.el9_6, kernel-64k-core-5.14.0-570.119.1.el9_6 +28
- Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.119.1.el9_6, kernel-rt-64k-5.14.0-570.119.1.el9_6, kernel-rt-64k-core-5.14.0-570.119.1.el9_6 +21
- Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.119.1.el9_6, kernel-rt-core-5.14.0-570.119.1.el9_6, kernel-rt-debug-5.14.0-570.119.1.el9_6 +11
- RHSA-2026:21556 Released 2026-05-28 · Red Hat rating Importantkernel security update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.12.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.12.1.el9_8, kernel-64k-devel-5.14.0-687.12.1.el9_8 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.12.1.el9_8, kernel-64k-5.14.0-687.12.1.el9_8, kernel-64k-core-5.14.0-687.12.1.el9_8 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.12.1.el9_8, libperf-5.14.0-687.12.1.el9_8
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.12.1.el9_8, kernel-rt-64k-5.14.0-687.12.1.el9_8, kernel-rt-64k-core-5.14.0-687.12.1.el9_8 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.12.1.el9_8, kernel-rt-core-5.14.0-687.12.1.el9_8, kernel-rt-debug-5.14.0-687.12.1.el9_8 +9
- RHSA-2026:21209 Released 2026-05-27 · Red Hat rating Importantkernel security update
- Red Hat CodeReady Linux Builder EUS (v.9.4) kernel-tools-libs-devel-5.14.0-427.127.1.el9_4, libperf-5.14.0-427.127.1.el9_4
- Red Hat Enterprise Linux AppStream EUS (v.9.4) kernel-64k-debug-devel-5.14.0-427.127.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.127.1.el9_4, kernel-64k-devel-5.14.0-427.127.1.el9_4 +11
- Red Hat Enterprise Linux BaseOS EUS (v.9.4) bpftool-7.3.0-427.127.1.el9_4, kernel-5.14.0-427.127.1.el9_4, kernel-64k-5.14.0-427.127.1.el9_4 +29
- Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt-5.14.0-427.127.1.el9_4, kernel-rt-core-5.14.0-427.127.1.el9_4, kernel-rt-debug-5.14.0-427.127.1.el9_4 +9
- Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4) kernel-rt-5.14.0-427.127.1.el9_4, kernel-rt-core-5.14.0-427.127.1.el9_4, kernel-rt-debug-5.14.0-427.127.1.el9_4 +11
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat CodeReady Linux Builder EUS (v.9.4) | Fixed | RHSA-2026:21209 |
| Red Hat CodeReady Linux Builder EUS (v.9.6) | Fixed | RHSA-2026:23224 |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:23329 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:21556 |
| Red Hat Enterprise Linux AppStream E4S (v.9.2) | Fixed | RHSA-2026:26515 |
| Red Hat Enterprise Linux AppStream EUS (v. 10.0) | Fixed | RHSA-2026:24343 |
| Red Hat Enterprise Linux AppStream EUS (v.9.4) | Fixed | RHSA-2026:21209 |
| Red Hat Enterprise Linux AppStream EUS (v.9.6) | Fixed | RHSA-2026:23224 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:23329 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2026:25121 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:21556 |
| Red Hat Enterprise Linux BaseOS AUS (v.8.4) | Fixed | RHSA-2026:26535 |
| Red Hat Enterprise Linux BaseOS AUS (v.8.6) | Fixed | RHSA-2026:25533 |
| Red Hat Enterprise Linux BaseOS E4S (v.8.8) | Fixed | RHSA-2026:26563 |
| Red Hat Enterprise Linux BaseOS E4S (v.9.2) | Fixed | RHSA-2026:26515 |
| Red Hat Enterprise Linux BaseOS EUS (v. 10.0) | Fixed | RHSA-2026:24343 |
| Red Hat Enterprise Linux BaseOS EUS (v.9.4) | Fixed | RHSA-2026:21209 |
| Red Hat Enterprise Linux BaseOS EUS (v.9.6) | Fixed | RHSA-2026:23224 |
| Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) | Fixed | RHSA-2026:26535 |
| Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) | Fixed | RHSA-2026:25533 |
| Red Hat Enterprise Linux BaseOS TUS (v.8.8) | Fixed | RHSA-2026:26563 |
| Red Hat Enterprise Linux CRB (v. 8) | Fixed | RHSA-2026:25121 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:23329 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:21556 |
| Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) | Fixed | RHSA-2026:24343 |
| Red Hat Enterprise Linux NFV (v. 8) | Fixed | RHSA-2026:25120 |
| Red Hat Enterprise Linux RT (v. 8) | Fixed | RHSA-2026:25120 |
| Red Hat Enterprise Linux Real Time (v. 10) | Fixed | RHSA-2026:23329 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2026:21556 |
| Red Hat Enterprise Linux Real Time E4S (v.9.2) | Fixed | RHSA-2026:26462 |
| Red Hat Enterprise Linux Real Time EUS (v. 10.0) | Fixed | RHSA-2026:24343 |
| Red Hat Enterprise Linux Real Time EUS (v.9.4) | Fixed | RHSA-2026:21209 |
| Red Hat Enterprise Linux Real Time EUS (v.9.6) | Fixed | RHSA-2026:23224 |
| Red Hat Enterprise Linux Real Time for NFV (v. 10) | Fixed | RHSA-2026:23329 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2026:21556 |
| Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) | Fixed | RHSA-2026:26462 |
| Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) | Fixed | RHSA-2026:24343 |
| Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4) | Fixed | RHSA-2026:21209 |
| Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) | Fixed | RHSA-2026:23224 |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2025-68366
- 2026-10-03 Alias added: GHSA-9x47-h3pc-w4pg
References
Other 8
- https://git.kernel.org/stable/c/330d688a5ca53857828081a3cf31b92ad1b0b3ed
- https://git.kernel.org/stable/c/cd93db1b1b4460e6ee77564024ea461e5940f69c
- https://git.kernel.org/stable/c/ae3e7bc1f4b393ae20e5c85583eb2c6977374716
- https://git.kernel.org/stable/c/2e5e0665a594f076ef2b9439447bae8be293d09d
- https://git.kernel.org/stable/c/c9b99c948b4fb014812afe7b5ccf2db121d22e46
- https://git.kernel.org/stable/c/9a38306643874566d20f7aba7dff9e6f657b51a9
- https://git.kernel.org/stable/c/c9e805f6a35d1dd189a9345595a5c20e87611942
- https://git.kernel.org/stable/c/1649714b930f9ea6233ce0810ba885999da3b5d4
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Sources
- CVE-2025-68366 · CVE Program
- CVE-2025-68366 · NVD
- FIRST EPSS
- GHSA-9x47-h3pc-w4pg · GitHub Advisory Database · CC BY 4.0
- CVE-2025-68366 · Red Hat security data · CC BY 4.0
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