CVE-2026-63868
net: garp: fix unsigned integer underflow in garp_pdu_parse_attr
Description
In the Linux kernel, the following vulnerability has been resolved: net: garp: fix unsigned integer underflow in garp_pdu_parse_attr The receive-side GARP attribute parser computes dlen with reversed operands: dlen = sizeof(*ga) - ga->len; ga->len is the on-wire attribute length and includes the GARP attribute header. For normal attributes with data, ga->len is larger than sizeof(*ga), so the subtraction underflows in unsigned arithmetic. The resulting value is later passed to garp_attr_lookup(), whose length argument is u8. After truncation, the parsed data length usually no longer matches the length stored for locally registered attributes, so received Join/Leave events are ignored. This breaks the GARP receive path for common attributes, such as GVRP VLAN registration attributes. Compute the data length as the attribute length minus the header length.
INFO
Published Date :
July 19, 2026, 3:16 p.m.
Last Modified :
July 19, 2026, 3:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-63868
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
- Compute data length by subtracting header size from attribute size.
- Ensure correct data length calculation in garp_pdu_parse_attr.
- Apply the provided kernel patch for garp_pdu_parse_attr.
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-2026-63868.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-63868 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-2026-63868
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-2026-63868 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-63868 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.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 19, 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': 'eca9ebac651f774d8b10fce7c5d173c3c3d3394f', 'lessThan': '29f28172afb2ae7b31e9bf3e978396f20b381688', 'versionType': 'git'}, {'status': 'affected', 'version': 'eca9ebac651f774d8b10fce7c5d173c3c3d3394f', 'lessThan': '973cf7c433d27f4d9556d0b7c332543be7ed7a6e', 'versionType': 'git'}, {'status': 'affected', 'version': 'eca9ebac651f774d8b10fce7c5d173c3c3d3394f', 'lessThan': 'd8dcd14aa886b8effd83022c550669f4f262854b', 'versionType': 'git'}, {'status': 'affected', 'version': 'eca9ebac651f774d8b10fce7c5d173c3c3d3394f', 'lessThan': '74e02121be1dcc0efcd56ebdf0171d6129105659', 'versionType': 'git'}, {'status': 'affected', 'version': 'eca9ebac651f774d8b10fce7c5d173c3c3d3394f', 'lessThan': 'd4c86ea09ae3e63ee5aa86e941fcc38e0e39874a', 'versionType': 'git'}, {'status': 'affected', 'version': 'eca9ebac651f774d8b10fce7c5d173c3c3d3394f', 'lessThan': '04e22fefac1af3e32f245e9045382348773b5d59', 'versionType': 'git'}, {'status': 'affected', 'version': 'eca9ebac651f774d8b10fce7c5d173c3c3d3394f', 'lessThan': 'a11f1a671b1361f0f1278dc0041374f2730df73f', 'versionType': 'git'}, {'status': 'affected', 'version': 'eca9ebac651f774d8b10fce7c5d173c3c3d3394f', 'lessThan': '16e408e607a94b646fb14a2a98422c6877ae4b3c', 'versionType': 'git'}], 'programFiles': ['net/802/garp.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2.6.27'}, {'status': 'unaffected', 'version': '0', 'lessThan': '2.6.27', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.259', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.210', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.176', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.143', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.94', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.36', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.13', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/802/garp.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: net: garp: fix unsigned integer underflow in garp_pdu_parse_attr The receive-side GARP attribute parser computes dlen with reversed operands: dlen = sizeof(*ga) - ga->len; ga->len is the on-wire attribute length and includes the GARP attribute header. For normal attributes with data, ga->len is larger than sizeof(*ga), so the subtraction underflows in unsigned arithmetic. The resulting value is later passed to garp_attr_lookup(), whose length argument is u8. After truncation, the parsed data length usually no longer matches the length stored for locally registered attributes, so received Join/Leave events are ignored. This breaks the GARP receive path for common attributes, such as GVRP VLAN registration attributes. Compute the data length as the attribute length minus the header length. Added Reference https://git.kernel.org/stable/c/04e22fefac1af3e32f245e9045382348773b5d59 Added Reference https://git.kernel.org/stable/c/16e408e607a94b646fb14a2a98422c6877ae4b3c Added Reference https://git.kernel.org/stable/c/29f28172afb2ae7b31e9bf3e978396f20b381688 Added Reference https://git.kernel.org/stable/c/74e02121be1dcc0efcd56ebdf0171d6129105659 Added Reference https://git.kernel.org/stable/c/973cf7c433d27f4d9556d0b7c332543be7ed7a6e Added Reference https://git.kernel.org/stable/c/a11f1a671b1361f0f1278dc0041374f2730df73f Added Reference https://git.kernel.org/stable/c/d4c86ea09ae3e63ee5aa86e941fcc38e0e39874a Added Reference https://git.kernel.org/stable/c/d8dcd14aa886b8effd83022c550669f4f262854b