CVE-2026-74659
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.
Affected versions
Linux kernel versions
5.14
and later are affected. Fixed in
5.15.216,
6.1.183,
6.6.152,
6.12.104,
6.18.45,
7.1.9,
7.2
and their respective stable series.
References
7 totalFrequently asked questions
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What is CVE-2026-74659?
CVE-2026-74659 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.14 onward and has been patched in 5.15.216, 6.1.183, 6.6.152 and others. CVE-2026-74659 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-74659?
Yes. CVE-2026-74659 has been patched. Fixed versions include 5.15.216, 6.1.183, 6.6.152 and others. If you are running Linux kernel 5.14 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-74659 actively exploited?
No. CVE-2026-74659 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.