Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ibmveth: Disable GSO for packets with small MSS Some physical adapters on Power systems do not support segmentation offload when the MSS is less than 224 bytes. Attempting to send such packets causes the adapter to freeze, stopping all traffic until manually reset. Implement ndo_features_check to disable GSO for packets with small MSS values. The network stack will perform software segmentation instead. The 224-byte minimum matches ibmvnic commit <f10b09ef687f> ("ibmvnic: Enforce stronger sanity checks on GSO packets") which uses the same physical adapters in SEA configurations. The issue occurs specifically when the hardware attempts to perform segmentation (gso_segs > 1) with a small MSS. Single-segment GSO packets (gso_segs == 1) do not trigger the problematic LSO code path and are transmitted normally without segmentation. Add an ndo_features_check callback to disable GSO when MSS < 224 bytes. Also call vlan_features_check() to ensure proper handling of VLAN packets, particularly QinQ (802.1ad) configurations where the hardware parser may not support certain offload features. Validated using iptables to force small MSS values. Without the fix, the adapter freezes. With the fix, packets are segmented in software and transmission succeeds. Comprehensive regression testing completedd (MSS tests, performance, stability).
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 4.2, < 5.10.258 |
Related Weaknesses (CWE)
References
- https://git.kernel.org/stable/c/1cdf5dbcec988d06f5f720bdf89e91073f77fa10Patch
- https://git.kernel.org/stable/c/3af24f0c4c31f18a4a2d927990759194832bb6e9Patch
- https://git.kernel.org/stable/c/82bc89fbb82d9396fb4eaee8720ea85e2e787957Patch
- https://git.kernel.org/stable/c/86fc64584811d43c9ccd74447de58620189d8b77Patch
- https://git.kernel.org/stable/c/9a5e984d7af910e46dcbed3ce77873e000a4f77dPatch
- https://git.kernel.org/stable/c/c1f261863e65b508f37416dfbc5c5d911c9b9233Patch
- https://git.kernel.org/stable/c/cc427d24ac6442ffdeafd157a63c7c5b73ed4de4Patch
- https://git.kernel.org/stable/c/db8012c631cb845e9ae2b4b531e17d86c9519755Patch
FAQ
What is CVE-2026-46273?
CVE-2026-46273 is a vulnerability with a CVSS score of 8.6 (HIGH). In the Linux kernel, the following vulnerability has been resolved: ibmveth: Disable GSO for packets with small MSS Some physical adapters on Power systems do not support segmentation offload when t...
How severe is CVE-2026-46273?
CVE-2026-46273 has been rated HIGH with a CVSS base score of 8.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-46273?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.