From $URL: CVE-2012-6536 ecd7918745234e423dd87fcc0c077da557909720 CVE-2012-6537 1f86840f897717f86d523a13e99a447e6a5d2fa5 7b789836f434c87168eab067cfbed1ec4783dffd f778a636713a435d3a922c60b1622a91136560c1 CVE-2012-6538 4c87308bdea31a7b4828a51f6156e6f721a1fcc9 CVE-2012-6539 43da5f2e0d0c69ded3d51907d9552310a6b545e8 CVE-2012-6540 2d8a041b7bfe1097af21441cb77d6af95f4f4680 CVE-2012-6541 7b07f8eb75aa3097cdfd4f6eac3da49db787381d CVE-2012-6542 3592aaeb80290bda0f2cf0b5456c97bfc638b192 CVE-2012-6543 04d4fbca1017c11381e7d82acea21dd741e748bc CVE-2012-6544 792039c73cf176c8e39a6e8beef2c94ff46522ed 3f68ba07b1da811bf383b4b701b129bfcb2e4988 e15ca9a0ef9a86f0477530b0f44a725d67f889ee CVE-2012-6545 9344a972961d1a6d2c04d9008b13617bcb6ec2ef f9432c5ec8b1e9a09b9b0e5569e3c73db8de432a 9ad2de43f1aee7e7274a4e0d41465489299e344b CVE-2012-6546 3c0c5cfdcd4d69ffc4b9c0907cec99039f30a50a e862f1a9b7df4e8196ebec45ac62295138aa3fc2 CVE-2012-6547 a117dacde0288f3ec60b6e5bcedae8fa37ee0dfc CVE-2012-6548 0143fc5e9f6f5aad4764801015bc8d4b4a278200 CVE-2012-6549 fe685aabf7c8c9f138e5ea900954d295bf229175 The number obviously indicates the commit n.
There are no longer any 2.x or <3.6 kernels available in the repository with the exception of sys-kernel/xbox-sources which is unsupported by security.