PT-2026-46036 · Linux · Linux
Published
2026-06-03
·
Updated
2026-06-03
·
CVE-2026-46273
None
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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 ("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).
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Related Identifiers
Affected Products
Linux