CVE-2026-23254
net: gro: fix outer network offset
Reported by linux · Published March 18, 2026
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().
EPSS 0.12% · 1.7th percentile
Fixed versions
Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.
| Package | Ecosystem | Fixed in |
|---|---|---|
| kernel6.12-modules-extra-common | Amazon Linux | 1:6.12.73-95.123.amzn2023 |
| kernel6.12-devel | Amazon Linux | 1:6.12.73-95.123.amzn2023 |
| bpftool6.12 | Amazon Linux | 1:6.12.73-95.123.amzn2023 |
| kernel6.18-devel | Amazon Linux | 1:6.18.15-14.217.amzn2023 |
| kernel6.12-headers | Amazon Linux | 1:6.12.73-95.123.amzn2023 |
| kernel6.18-tools-devel | Amazon Linux | 1:6.18.15-14.217.amzn2023 |
| python3-perf6.18 | Amazon Linux | 1:6.18.15-14.217.amzn2023 |
| kernel6.12-libbpf | Amazon Linux | 1:6.12.73-95.123.amzn2023 |
| kernel6.18-modules-extra-common | Amazon Linux | 1:6.18.15-14.217.amzn2023 |
| kernel6.18 | Amazon Linux | 1:6.18.15-14.217.amzn2023 |
| kernel-livepatch-6.12.73-95.123 | Amazon Linux | 1:1.0-0.amzn2023 |
| kernel6.18-libbpf-devel | Amazon Linux | 1:6.18.15-14.217.amzn2023 |
9 more packages have a fixed version. See every fix in Lookup.
Risk scores
Affected products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | af276a5ac8e938c8b058e3e124073cc1e322d98b, 5ef31ea5d053a8f493a772ebad3f3ce82c35d845, 5ef31ea5d053a8f493a772ebad3f3ce82c35d845 |
| Linux | Linux | 6.9, 0, 6.6.124 |
| amazon:2023 | kernel6.12-modules-extra-common | 0 |
| amazon:2023 | kernel6.12-devel | 0 |
| amazon:2023 | bpftool6.12 | 0 |
| amazon:2023 | kernel6.18-devel | 0 |
| amazon:2023 | kernel6.12-headers | 0 |
| amazon:2023 | kernel6.18-tools-devel | 0 |
| amazon:2023 | python3-perf6.18 | 0 |
| amazon:2023 | kernel6.12-libbpf | 0 |
| amazon:2023 | kernel6.18-modules-extra-common | 0 |
| amazon:2023 | kernel6.18 | 0 |
| amazon:2023 | kernel-livepatch-6.12.73-95.123 | 0 |
| amazon:2023 | kernel6.18-libbpf-devel | 0 |
| amazon:2023 | kernel6.18-libbpf | 0 |
| amazon:2023 | perf6.18 | 0 |
| amazon:2023 | kernel6.12-tools | 0 |
| amazon:2023 | kernel6.18-tools | 0 |
| amazon:2023 | kernel6.18-headers | 0 |
| amazon:2023 | kernel6.12 | 0 |
…and 12 more
Timeline
- Mar 18, 2026 CVE Published
- Mar 19, 2026 EPSS Score (27 in total, the first dated here)
- Mar 22, 2026 Coalition ESS Score (2 in total, the first dated here)
- Mar 29, 2026 Security Advisory (91 in total, the first dated here)
- May 28, 2026 Distribution Patch (86 in total, the first dated here)
Query this with the API
The same record, from the CLI:
vulnetix vdb vuln CVE-2026-23254
vulnetix vdb fixes CVE-2026-23254Or with curl, using the org id and key from your account page:
curl -s -H "Authorization: ApiKey ${VULNETIX_ORG_ID}:${VULNETIX_API_KEY}" \
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