{"id":"CVE-2026-23243","summary":"RDMA/umad: Reject negative data_len in ib_umad_write","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/umad: Reject negative data_len in ib_umad_write\n\nib_umad_write computes data_len from user-controlled count and the\nMAD header sizes. With a mismatched user MAD header size and RMPP\nheader length, data_len can become negative and reach ib_create_send_mad().\nThis can make the padding calculation exceed the segment size and trigger\nan out-of-bounds memset in alloc_send_rmpp_list().\n\nAdd an explicit check to reject negative data_len before creating the\nsend buffer.\n\nKASAN splat:\n[  211.363464] BUG: KASAN: slab-out-of-bounds in ib_create_send_mad+0xa01/0x11b0\n[  211.364077] Write of size 220 at addr ffff88800c3fa1f8 by task spray_thread/102\n[  211.365867] ib_create_send_mad+0xa01/0x11b0\n[  211.365887] ib_umad_write+0x853/0x1c80","modified":"2026-04-16T08:44:12.263171925Z","published":"2026-03-18T10:05:05.826Z","related":["SUSE-SU-2026:1342-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23243.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1371ef6b1ecf3676b8942f5dfb3634fb0648128e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/205955f29c26330b1dc7fdeadd5bb97c38e26f56"},{"type":"WEB","url":"https://git.kernel.org/stable/c/362e45fd9069ffa1523f9f1633b606ebf72060d7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/52ab82cc5cf8ada5c3fb6ffe8f32fdb2fc27a34b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5551b02fdbfd85a325bb857f3a8f9c9f33397ed2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6eb2919474ca105c5b13d19574e25f0ddcf19ca2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9c80d688f402539dfc8f336de1380d6b4ee14316"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a6a3e4af10993cb9e4b8f0548680aba0ab5f3b0d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23243.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23243"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"2be8e3ee8efd6f99ce454115c29d09750915021a"},{"fixed":"1371ef6b1ecf3676b8942f5dfb3634fb0648128e"},{"fixed":"362e45fd9069ffa1523f9f1633b606ebf72060d7"},{"fixed":"6eb2919474ca105c5b13d19574e25f0ddcf19ca2"},{"fixed":"a6a3e4af10993cb9e4b8f0548680aba0ab5f3b0d"},{"fixed":"9c80d688f402539dfc8f336de1380d6b4ee14316"},{"fixed":"205955f29c26330b1dc7fdeadd5bb97c38e26f56"},{"fixed":"52ab82cc5cf8ada5c3fb6ffe8f32fdb2fc27a34b"},{"fixed":"5551b02fdbfd85a325bb857f3a8f9c9f33397ed2"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23243.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.24"},{"fixed":"5.10.252"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.202"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.165"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.128"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.75"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.14"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23243.json"}}],"schema_version":"1.7.5"}