net: garp: fix unsigned integer underflow in garp_pdu_parse_attr

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63868
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 15:16:53 UTC
Updated2026-07-19 15:16:53 UTC
DescriptionIn 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.

Risk And Classification

EPSS: 0.001650000 probability, percentile 0.060630000 (date 2026-07-20)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected eca9ebac651f774d8b10fce7c5d173c3c3d3394f 29f28172afb2ae7b31e9bf3e978396f20b381688 git Not specified
CNA Linux Linux affected eca9ebac651f774d8b10fce7c5d173c3c3d3394f 973cf7c433d27f4d9556d0b7c332543be7ed7a6e git Not specified
CNA Linux Linux affected eca9ebac651f774d8b10fce7c5d173c3c3d3394f d8dcd14aa886b8effd83022c550669f4f262854b git Not specified
CNA Linux Linux affected eca9ebac651f774d8b10fce7c5d173c3c3d3394f 74e02121be1dcc0efcd56ebdf0171d6129105659 git Not specified
CNA Linux Linux affected eca9ebac651f774d8b10fce7c5d173c3c3d3394f d4c86ea09ae3e63ee5aa86e941fcc38e0e39874a git Not specified
CNA Linux Linux affected eca9ebac651f774d8b10fce7c5d173c3c3d3394f 04e22fefac1af3e32f245e9045382348773b5d59 git Not specified
CNA Linux Linux affected eca9ebac651f774d8b10fce7c5d173c3c3d3394f a11f1a671b1361f0f1278dc0041374f2730df73f git Not specified
CNA Linux Linux affected eca9ebac651f774d8b10fce7c5d173c3c3d3394f 16e408e607a94b646fb14a2a98422c6877ae4b3c git Not specified
CNA Linux Linux affected 2.6.27 Not specified
CNA Linux Linux unaffected 2.6.27 semver Not specified
CNA Linux Linux unaffected 5.10.259 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.210 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.176 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.143 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.94 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.36 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.13 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/d4c86ea09ae3e63ee5aa86e941fcc38e0e39874a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/74e02121be1dcc0efcd56ebdf0171d6129105659 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/04e22fefac1af3e32f245e9045382348773b5d59 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/973cf7c433d27f4d9556d0b7c332543be7ed7a6e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a11f1a671b1361f0f1278dc0041374f2730df73f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d8dcd14aa886b8effd83022c550669f4f262854b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/16e408e607a94b646fb14a2a98422c6877ae4b3c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/29f28172afb2ae7b31e9bf3e978396f20b381688 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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