net: gro: fix outer network offset
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: 1 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: net: gro: fix outer network offset The udp GRO complete stage assumes that all the packets inserted the RX have the `encapsulation` flag zeroed. Such assumption is not true, as a few H/W NICs can set such flag when H/W offloading the checksum for an UDP encapsulated traffic, the tun driver can inject GSO packets with UDP encapsulation and the problematic layout can also be created via a veth based setup. Due to the above, in the problematic scenarios, udp4_gro_complete() uses the wrong network offset (inner instead of outer) to compute the outer UDP header pseudo checksum, leading to csum validation errors later on in packet processing. Address the issue always clearing the encapsulation flag at GRO completion time. Such flag will be set again as needed for encapsulated packets by udp_gro_complete().
Why it matters now
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 | 6.6.31 to before 6.6.124; 6.8.10 to before 6.9 | 6.6.124, 6.9 | Patch available | CNA |
| Linux | Linux | 6.9 and later | 6.6.124, 6.12.70, 6.18.10, 6.19 | Patch available | CNA |
- Linux VendorLinux Affected 6.6.31 to before 6.6.124; 6.8.10 to before 6.9 Fixed in 6.6.124, 6.9 Patch available CNA
- Linux VendorLinux Affected 6.9 and later Fixed in 6.6.124, 6.12.70, 6.18.10, 6.19 Patch available CNA
CPE configurations NVD · 11
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 6.6.31 to before 6.6.124; 6.8.10 to before 6.9; 6.9.1 to before 6.12.70; 6.13 to before 6.18.10 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.9:-:*:*:*:*:*:* | 6.9 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.9:rc7:*:*:*:*:*:* | 6.9 rc7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:* | 6.19 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:* | 6.19 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:* | 6.19 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:* | 6.19 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:* | 6.19 rc5 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:* | 6.19 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:* | 6.19 rc7 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.6.31 to before 6.6.124; 6.8.10 to before 6.9; 6.9.1 to before 6.12.70; 6.13 to before 6.18.10 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.9:-:*:*:*:*:*:* Versions 6.9 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.9:rc7:*:*:*:*:*:* Versions 6.9 rc7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:* Versions 6.19 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:* Versions 6.19 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:* Versions 6.19 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:* Versions 6.19 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:* Versions 6.19 rc5 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:* Versions 6.19 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:* Versions 6.19 rc7 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.124, 6.9
- Fix · CNA Linux (Linux) Fixed in 6.6.124, 6.12.70, 6.18.10, 6.19
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-23254
- 2026-10-03 Alias added: GHSA-wjrj-hvqv-fw2v
References
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- 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-2026-23254 · CVE Program
- CVE-2026-23254 · NVD
- FIRST EPSS
- GHSA-wjrj-hvqv-fw2v · GitHub Advisory Database · CC BY 4.0
- CVE-2026-23254 · Red Hat security data · CC BY 4.0
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