# CVE-2026-46273: ibmveth: Disable GSO for packets with small MSS CVE-2026-46273 is fixed in 17 products on 1 platform, first by DEBIAN-CVE-2026-46273, released June 24, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-46273 - Priority: High - CVSS: 8.6 (Moderate) - EPSS: 0.0039 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 3, 2026 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-46273 ## 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 ("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). ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.63.1 | [SUSE-SU-2026:2722-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2722-1.md) | Jul 1, 2026 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-azure sles 15.7 | 6.4.0-150700.53.63.1 | [SUSE-SU-2026:2722-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2722-1.md) | Jul 1, 2026 | | Linux | kernel-azure sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-default sles 15.6 | 6.4.0-150600.23.118.1 | [SUSE-SU-2026:2632-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2632-1.md) | Jun 25, 2026 | | Linux | kernel-default sles 15.7 | 6.4.0-150700.53.63.1 | [SUSE-SU-2026:2722-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2722-1.md) | Jul 1, 2026 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23237-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23237-1.md) | Aug 11, 2026 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.37.1.160000.2.19 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-default-base sles 15.6 | 6.4.0-150600.23.118.1.150600.12.56.1 | [SUSE-SU-2026:2632-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2632-1.md) | Jun 25, 2026 | | Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.63.1.150700.17.37.1 | [SUSE-SU-2026:2722-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2722-1.md) | Jul 1, 2026 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.37.1.160000.2.19 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-docs sles 15.6 | 6.4.0-150600.23.118.1 | [SUSE-SU-2026:2632-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2632-1.md) | Jun 25, 2026 | | Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.63.1 | [SUSE-SU-2026:2722-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2722-1.md) | Jul 1, 2026 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-livepatch-SLE15-SP6_Update_28 sles 15.6 | 1-150600.13.3.1 | [SUSE-SU-2026:2632-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2632-1.md) | Jun 25, 2026 | | Linux | kernel-livepatch-SLE15-SP7-RT_Update_17 sles 15.7 | 1-150700.1.3.1 | [SUSE-SU-2026:2799-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2799-1.md) | Jul 8, 2026 | | Linux | kernel-livepatch-SLE15-SP7_Update_17 sles 15.7 | 1-150700.15.3.1 | [SUSE-SU-2026:2722-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2722-1.md) | Jul 1, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-obs-build sles 15.6 | 6.4.0-150600.23.118.1 | [SUSE-SU-2026:2632-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2632-1.md) | Jun 25, 2026 | | Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.63.1 | [SUSE-SU-2026:2722-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2722-1.md) | Jul 1, 2026 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-source sles 15.6 | 6.4.0-150600.23.118.1 | [SUSE-SU-2026:2632-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2632-1.md) | Jun 25, 2026 | | Linux | kernel-source sles 15.7 | 6.4.0-150700.53.63.1 | [SUSE-SU-2026:2722-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2722-1.md) | Jul 1, 2026 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-syms sles 15.6 | 6.4.0-150600.23.118.1 | [SUSE-SU-2026:2632-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2632-1.md) | Jun 25, 2026 | | Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.63.1 | [SUSE-SU-2026:2722-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2722-1.md) | Jul 1, 2026 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 | | Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.63.1 | [SUSE-SU-2026:2722-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2722-1.md) | Jul 1, 2026 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 | | Linux | linux Debian 12.15 (bookworm) | 6.1.176-1 | [DEBIAN-CVE-2026-46273](https://patchblox.com/security/data/fix/linux/debian-cve-2026-46273.md) | Jun 24, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.88-1 | [DEBIAN-CVE-2026-46273](https://patchblox.com/security/data/fix/linux/debian-cve-2026-46273.md) | Jun 24, 2026 | | Linux | linux Debian 14 | 7.0.7-1 | [DEBIAN-CVE-2026-46273](https://patchblox.com/security/data/fix/linux/debian-cve-2026-46273.md) | Jun 24, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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