{"id":"CVE-2026-89532","revision":"fa4d4df7bc8f433bb37163626ab01ef5","records":[{"revision":"fa4d4df7bc8f433bb37163626ab01ef5","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89532","aliases":[],"title":"svcrdma: Fix pcl_for_each_segment for empty chunks","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: Fix pcl_for_each_segment for empty chunks\n\nWhen a parsed chunk list contains a chunk whose ch_segcount is zero,\npcl_for_each_segment computes its inclusive upper bound as\n&chunk->ch_segments[ch_segcount - 1]. ch_segcount is u32, so the\nsubtraction wraps to 0xFFFFFFFF and the bound lands far past the\nch_segments flex array. The loop body then walks unrelated memory at\nsizeof(struct svc_rdma_segment) stride until it faults.\n\nA zero-segcount chunk is reachable from the wire:\nxdr_check_write_chunk() only rejects segcount values greater than\nrc_maxpages, and pcl_alloc_write() links a freshly allocated chunk\nonto rc_write_pcl/rc_reply_pcl before its segment-fill loop runs,\nso a Write or Reply chunk advertising zero segments leaves\nch_segcount == 0 on the list. When the transport has negotiated\nSend-With-Invalidate, svc_rdma_get_inv_rkey() iterates all four\nPCLs with pcl_for_each_segment and dereferences segment->rs_handle\non each iteration, turning the underflow into an out-of-bounds read\nand a general protection fault.\n\n    xdr_check_write_list / xdr_check_reply_chunk\n      pcl_alloc_write()\n        chunk = pcl_alloc_chunk(...)  /* ch_segcount = 0 */\n        list_add_tail(&chunk->ch_list, &pcl->cl_chunks)\n        /* fill loop iterates zero times for wire segcount 0 */\n\n    svc_rdma_get_inv_rkey()\n      pcl_for_each_chunk(rc_write_pcl)\n        pcl_for_each_segment(segment, chunk)\n          pos <= &ch_segments[0u - 1u]  /* 0xFFFFFFFF */\n          segment->rs_handle            /* OOB read -> GPF */\n\nFix by switching the macro to a half-open upper bound that uses\nch_segcount directly. For ch_segcount == 0 the loop start equals the\nloop end and the body is skipped; for ch_segcount > 0 the iteration\nrange is unchanged. All six existing call sites in\nnet/sunrpc/xprtrdma/svc_rdma_recvfrom.c and\nnet/sunrpc/xprtrdma/svc_rdma_rw.c remain correct under the new bound,\nso no caller changes are needed.","state":0,"publishedAt":"2026-09-11T19:44:11.495+00:00","modifiedAt":"2026-10-19T08:48:23.895+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"include/linux/sunrpc/svc_rdma_pcl.h\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"78147ca8b4a9b6cf0e597ddd6bf17959e08376c2\",\n                            \"lessThan\": \"1e2e3481e39103a386b86be1c33eaef97cbdf16e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"78147ca8b4a9b6cf0e597ddd6bf17959e08376c2\",\n                            \"lessThan\": \"3a78b841879c2a3243f74edc514236fb2907167f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"78147ca8b4a9b6cf0e597ddd6bf17959e08376c2\",\n                            \"lessThan\": \"06d0390c37fa6714624af771bd72bbf1a7ed9bb1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"78147ca8b4a9b6cf0e597ddd6bf17959e08376c2\",\n                            \"lessThan\": \"9c5a03c3dc505c0295339b0a1b9e4fe36447e482\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"78147ca8b4a9b6cf0e597ddd6bf17959e08376c2\",\n                            \"lessThan\": \"a1c954ca4977a4e6ec73ef92fe48073ec54f9fc8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"78147ca8b4a9b6cf0e597ddd6bf17959e08376c2\",\n                            \"lessThan\": \"6d33a7e6bf6c6b293a266a617201285a1ad32c56\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"78147ca8b4a9b6cf0e597ddd6bf17959e08376c2\",\n                            \"lessThan\": \"b7713a784c59515d0aba558c8f5df6a0164dd3a9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"include/linux/sunrpc/svc_rdma_pcl.h\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.11\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.11\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.109\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","score":9.1,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/1e2e3481e39103a386b86be1c33eaef97cbdf16e","https://git.kernel.org/stable/c/3a78b841879c2a3243f74edc514236fb2907167f","https://git.kernel.org/stable/c/06d0390c37fa6714624af771bd72bbf1a7ed9bb1","https://git.kernel.org/stable/c/9c5a03c3dc505c0295339b0a1b9e4fe36447e482","https://git.kernel.org/stable/c/a1c954ca4977a4e6ec73ef92fe48073ec54f9fc8","https://git.kernel.org/stable/c/6d33a7e6bf6c6b293a266a617201285a1ad32c56","https://git.kernel.org/stable/c/b7713a784c59515d0aba558c8f5df6a0164dd3a9"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89532","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89532","identifiers":["CVE-2026-89532"]},"retained":false,"historicalAffected":[]}],"coverage":[]}