# CVE-2026-74659: net: bridge: mrp: fix uninitialised bytes on the wire CVE-2026-74659 is fixed in 17 products on 1 platform, first by DEBIAN-CVE-2026-74659, released August 27, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-74659 - Priority: Routine - CVSS: 2.3 (Low) - EPSS: 0.0017 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Aug 22, 2026 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74659 ## Description In the Linux kernel, the following vulnerability has been resolved: net: bridge: mrp: fix uninitialised bytes on the wire br_mrp_alloc_test_skb() builds MRP test frames on an skb from dev_alloc_skb(), which does not clear the linear data area. On the MRA ring-role branch the sub-option TLV header is appended with sub_tlv = skb_put(skb, sizeof(*sub_tlv)); sub_tlv->type = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR; so sub_tlv->length is never written, and the two trailing alignment bytes are appended with a bare skb_put() that does not clear them either. The neighbouring oui and sub_opt regions are explicitly zeroed, so three uninitialised bytes are left in every MRA MRP_Test frame that goes out. Put the sub-option TLV header and the alignment padding in a single skb_put_zero(), which clears both. The AUTO_MGR sub-TLV carries no payload, so the zeroed length field is already the value it should have. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.84.1 | [SUSE-SU-2026:4706-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4706-1.md) | Nov 7, 2026 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-azure sles 15.7 | 6.4.0-150700.53.84.1 | [SUSE-SU-2026:4706-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4706-1.md) | Nov 7, 2026 | | Linux | kernel-azure sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-default sles 15.7 | 6.4.0-150700.53.84.1 | [SUSE-SU-2026:4706-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4706-1.md) | Nov 7, 2026 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24197-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24197-1.md) | Nov 7, 2026 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.39.1.160000.2.25 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.84.1.150700.17.47.1 | [SUSE-SU-2026:4706-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4706-1.md) | Nov 7, 2026 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.39.1.160000.2.26 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.84.1 | [SUSE-SU-2026:4706-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4706-1.md) | Nov 7, 2026 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-livepatch-SLE15-SP7-RT_Update_21 sles 15.7 | 1-150700.1.3.1 | [SUSE-SU-2026:4640-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4640-1.md) | Nov 7, 2026 | | Linux | kernel-livepatch-SLE15-SP7_Update_22 sles 15.7 | 1-150700.15.3.1 | [SUSE-SU-2026:4706-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4706-1.md) | Nov 7, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.84.1 | [SUSE-SU-2026:4706-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4706-1.md) | Nov 7, 2026 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-source sles 15.7 | 6.4.0-150700.53.84.1 | [SUSE-SU-2026:4706-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4706-1.md) | Nov 7, 2026 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.84.1 | [SUSE-SU-2026:4706-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4706-1.md) | Nov 7, 2026 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.39.1 | [OPENSUSE-SU-2026:22091-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22091-1.md) | Nov 7, 2026 | | Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.84.1 | [SUSE-SU-2026:4706-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4706-1.md) | Nov 7, 2026 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.39.1 | [SUSE-SU-2026:24235-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24235-1.md) | Nov 7, 2026 | | Linux | linux Debian 12.15 (bookworm) | 6.1.187-1 | [DEBIAN-CVE-2026-74659](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74659.md) | Aug 27, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.105-1 | [DEBIAN-CVE-2026-74659](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74659.md) | Aug 27, 2026 | | Linux | linux Debian 14 | 7.1.9-1 | [DEBIAN-CVE-2026-74659](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74659.md) | Aug 27, 2026 | | Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.107-1~deb12u1 | [DEBIAN-CVE-2026-74659](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74659.md) | Aug 27, 2026 | --- Data as of 2026-11-08T19:12:23Z UTC. 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