vrf: use RCU protection in l3mdev_l3_out()
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 15 fixed, 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.
Summary
In the Linux kernel, the following vulnerability has been resolved: vrf: use RCU protection in l3mdev_l3_out() l3mdev_l3_out() can be called without RCU being held: raw_sendmsg() ip_push_pending_frames() ip_send_skb() ip_local_out() __ip_local_out() l3mdev_ip_out() Add rcu_read_lock() / rcu_read_unlock() pair to avoid a potential UAF.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
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 | 4.9 and later | 5.4.291, 5.10.235, 5.15.179, 6.1.129, 6.6.79, 6.12.16, 6.13.4, 6.14 | Patch available | CNA |
- Linux VendorLinux Affected 4.9 and later Fixed in 5.4.291, 5.10.235, 5.15.179, 6.1.129, 6.6.79, 6.12.16, 6.13.4, 6.14 Patch available CNA
CPE configurations NVD · 3
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 4.9 to before 6.1.129; 6.2 to before 6.6.79; 6.7 to before 6.12.16; 6.13 to before 6.13.4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:* | 6.14 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:* | 6.14 rc2 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.9 to before 6.1.129; 6.2 to before 6.6.79; 6.7 to before 6.12.16; 6.13 to before 6.13.4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:* Versions 6.14 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:* Versions 6.14 rc2 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.4.291, 5.10.235, 5.15.179, 6.1.129, 6.6.79, 6.12.16, 6.13.4, 6.14
Red Hat 3 advisories
- RHSA-2026:2352 Released 2026-02-09 · Red Hat rating Moderatekernel security update
- Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.86.1.el9_6, libperf-5.14.0-570.86.1.el9_6
- Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.86.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.86.1.el9_6, kernel-64k-devel-5.14.0-570.86.1.el9_6 +12
- Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.86.1.el9_6, kernel-64k-5.14.0-570.86.1.el9_6, kernel-64k-core-5.14.0-570.86.1.el9_6 +28
- Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.86.1.el9_6, kernel-rt-64k-5.14.0-570.86.1.el9_6, kernel-rt-64k-core-5.14.0-570.86.1.el9_6 +21
- Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.86.1.el9_6, kernel-rt-core-5.14.0-570.86.1.el9_6, kernel-rt-debug-5.14.0-570.86.1.el9_6 +11
- 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
- RHSA-2025:20095 Released 2025-11-11 · Red Hat rating Moderatekernel security update
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-124.8.1.el10_1, kernel-64k-debug-devel-matched-6.12.0-124.8.1.el10_1, kernel-64k-devel-6.12.0-124.8.1.el10_1 +12
- Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-124.8.1.el10_1, kernel-64k-6.12.0-124.8.1.el10_1, kernel-64k-core-6.12.0-124.8.1.el10_1 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-124.8.1.el10_1, libperf-6.12.0-124.8.1.el10_1
- Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-124.8.1.el10_1, kernel-rt-64k-6.12.0-124.8.1.el10_1, kernel-rt-64k-core-6.12.0-124.8.1.el10_1 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-124.8.1.el10_1, kernel-rt-core-6.12.0-124.8.1.el10_1, kernel-rt-debug-6.12.0-124.8.1.el10_1 +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 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 9 | Affected | No fix yet |
| Red Hat CodeReady Linux Builder EUS (v.9.6) | Fixed | RHSA-2026:2352 |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2025:20095 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2025:20518 |
| Red Hat Enterprise Linux AppStream EUS (v.9.6) | Fixed | RHSA-2026:2352 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2025:20095 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2025:20518 |
| Red Hat Enterprise Linux BaseOS EUS (v.9.6) | Fixed | RHSA-2026:2352 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2025:20095 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2025:20518 |
| Red Hat Enterprise Linux Real Time (v. 10) | Fixed | RHSA-2025:20095 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2025:20518 |
| Red Hat Enterprise Linux Real Time EUS (v.9.6) | Fixed | RHSA-2026:2352 |
| Red Hat Enterprise Linux Real Time for NFV (v. 10) | Fixed | RHSA-2025:20095 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2025:20518 |
| Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) | Fixed | RHSA-2026:2352 |
Timeline
- 2026-10-02 Threatist record created from CVE-2025-21791
- 2026-10-03 Alias added: GHSA-vr2w-w74g-r822
- 2026-10-29 Affected versions changed · Red Hat
References
Patch 8
- https://git.kernel.org/stable/c/6ccaa5797f5362a2aad6baa6ddaf4715ac2dd51e
- https://git.kernel.org/stable/c/20a3489b396764cc9376e32a9172bee26a89dc3b
- https://git.kernel.org/stable/c/5bb4228c32261d06e4fbece37ec3828bcc005b6b
- https://git.kernel.org/stable/c/c7574740be8ce68a57d0aece24987b9be2114c3c
- https://git.kernel.org/stable/c/c40cb5c03e37552d6eff963187109e2c3f78ef6f
- https://git.kernel.org/stable/c/022cac1c693add610ae76ede03adf4d9d5a2cf21
- https://git.kernel.org/stable/c/7b81425b517accefd46bee854d94954f5c57e019
- https://git.kernel.org/stable/c/6d0ce46a93135d96b7fa075a94a88fe0da8e8773
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- 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-2025-21791 · CVE Program
- CVE-2025-21791 · NVD
- FIRST EPSS
- GHSA-vr2w-w74g-r822 · GitHub Advisory Database · CC BY 4.0
- CVE-2025-21791 · Red Hat security data · CC BY 4.0
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