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CVE-2026-74659

net: bridge: mrp: fix uninitialised bytes on the wire PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
Linux / Linuxaffected f7458934b0791c39a001e4d902fc3bf697b439b5 before 014c062d23c63ec77ef2cf17a0d9363c7441cc94; affected f7458934b0791c39a001e4d902fc3bf697b439b5 before 7ebc23ff03668042e0b0e4034bb1518d36198d9e; affected f7458934b0791c39a001e4d902fc3bf697b439b5 before 06d58b8d2f053ced82e01efaeb6e7c82891eed58; affected f7458934b0791c39a001e4d902fc3bf697b439b5 before a5e385eeb2d6dbbbdebfa050e67c34734ae12693; affected f7458934b0791c39a001e4d902fc3bf697b439b5 before 5912cf1822fbe53ae275c147868740eb384a5d3e; affected f7458934b0791c39a001e4d902fc3bf697b439b5 before e08665218040f8e312abe40f74543186f3c2c941; affected f7458934b0791c39a001e4d902fc3bf697b439b5 before 63488dba65ef91373ef616575b32eb0eb21459f4
Linux / Linuxaffected 5.14; unaffected 0 before 5.14; unaffected 5.15.216 through 5.15.*; unaffected 6.1.183 through 6.1.*; unaffected 6.6.152 through 6.6.*; unaffected 6.12.104 through 6.12.*; unaffected 6.18.45 through 6.18.*; unaffected 7.1.9 through 7.1.*; unaffected 7.2 through *

CWE

No CWE identifiers supplied.

References