CVE-2026-74659
net: bridge: mrp: fix uninitialised bytes on the wire
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.
INFO
Published Date :
Aug. 22, 2026, 4:16 p.m.
Last Modified :
Aug. 22, 2026, 4:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-74659
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Apply kernel patches that zero memory before transmission.
- Ensure MRP test frames are properly initialized.
- Update the Linux kernel to the latest secure version.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-74659.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74659 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-74659
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-74659 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74659 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 22, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'f7458934b0791c39a001e4d902fc3bf697b439b5', 'lessThan': '014c062d23c63ec77ef2cf17a0d9363c7441cc94', 'versionType': 'git'}, {'status': 'affected', 'version': 'f7458934b0791c39a001e4d902fc3bf697b439b5', 'lessThan': '7ebc23ff03668042e0b0e4034bb1518d36198d9e', 'versionType': 'git'}, {'status': 'affected', 'version': 'f7458934b0791c39a001e4d902fc3bf697b439b5', 'lessThan': '06d58b8d2f053ced82e01efaeb6e7c82891eed58', 'versionType': 'git'}, {'status': 'affected', 'version': 'f7458934b0791c39a001e4d902fc3bf697b439b5', 'lessThan': 'a5e385eeb2d6dbbbdebfa050e67c34734ae12693', 'versionType': 'git'}, {'status': 'affected', 'version': 'f7458934b0791c39a001e4d902fc3bf697b439b5', 'lessThan': '5912cf1822fbe53ae275c147868740eb384a5d3e', 'versionType': 'git'}, {'status': 'affected', 'version': 'f7458934b0791c39a001e4d902fc3bf697b439b5', 'lessThan': 'e08665218040f8e312abe40f74543186f3c2c941', 'versionType': 'git'}, {'status': 'affected', 'version': 'f7458934b0791c39a001e4d902fc3bf697b439b5', 'lessThan': '63488dba65ef91373ef616575b32eb0eb21459f4', 'versionType': 'git'}], 'programFiles': ['net/bridge/br_mrp.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.14'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.14', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.15.216', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.183', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.152', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.104', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.45', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.9', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/bridge/br_mrp.c'], 'defaultStatus': 'affected'}] Added 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. Added Reference https://git.kernel.org/stable/c/014c062d23c63ec77ef2cf17a0d9363c7441cc94 Added Reference https://git.kernel.org/stable/c/06d58b8d2f053ced82e01efaeb6e7c82891eed58 Added Reference https://git.kernel.org/stable/c/5912cf1822fbe53ae275c147868740eb384a5d3e Added Reference https://git.kernel.org/stable/c/63488dba65ef91373ef616575b32eb0eb21459f4 Added Reference https://git.kernel.org/stable/c/7ebc23ff03668042e0b0e4034bb1518d36198d9e Added Reference https://git.kernel.org/stable/c/a5e385eeb2d6dbbbdebfa050e67c34734ae12693 Added Reference https://git.kernel.org/stable/c/e08665218040f8e312abe40f74543186f3c2c941