{"id":"CVE-2026-89541","revision":"244eb3cdef4f42a39adc68fe4250467f","records":[{"revision":"244eb3cdef4f42a39adc68fe4250467f","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89541","aliases":[],"title":"SUNRPC: harden gss_unwrap_resp_priv length checks","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: harden gss_unwrap_resp_priv length checks\n\ngss_unwrap_resp_priv() validates the RPCSEC_GSS opaque length with\n\n    offset = (u8 *)(p) - (u8 *)head->iov_base;\n    if (offset + opaque_len > rcv_buf->len)\n            goto unwrap_failed;\n    maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset,\n                          offset + opaque_len, rcv_buf);\n\nBoth operands are u32 and the sum is computed in u32. A reply with\nopaque_len near 0xffffffff makes offset + opaque_len wrap to a small\nvalue that is below rcv_buf->len, so the bound check passes and\ngss_unwrap() is called with end < begin. The check also lacks a\nlower bound, so any opaque_len in [0, GSS_KRB5_TOK_HDR_LEN) is\naccepted and forwarded to gss_krb5_unwrap_v2(), whose pre-decrypt\nheader reads at ptr+4 and ptr+6 then run past the token.\n\nA krb5p NFS server returning a crafted RPCSEC_GSS reply can drive\nthe client into out-of-bounds reads in gss_krb5_unwrap_v2() and the\nrotate_left() loop that follows.\n\nFix by replacing the single combined check with three guards that\nare safe in u32 arithmetic and that enforce the RFC 4121 minimum\nouter token length:\n\n    if (offset > rcv_buf->len)\n            goto unwrap_failed;\n    if (opaque_len > rcv_buf->len - offset)\n            goto unwrap_failed;\n    if (opaque_len < GSS_KRB5_TOK_HDR_LEN)\n            goto unwrap_failed;\n\nThe first guard makes the subtraction in the second guard\nunconditionally safe; offset is derived from a successful\nxdr_inline_decode() in the head kvec, so in practice it already\nsatisfies the bound. The floor mirrors the server-side check added\nin commit 5b757c2e57a5 (\"SUNRPC: svcauth_gss: enforce krb5 token\nminimum length\").","state":0,"publishedAt":"2026-09-11T19:44:18.188+00:00","modifiedAt":"2026-10-19T08:48:32.929+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                        \"net/sunrpc/auth_gss/auth_gss.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2d2da60c63b67174add32f06e8d54c3a0c5cd9cf\",\n                            \"lessThan\": \"3691c4b3488d8ca046b9941e5be30c626dbbbb50\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2d2da60c63b67174add32f06e8d54c3a0c5cd9cf\",\n                            \"lessThan\": \"85fa6b12e8f439739ac36ef2aad925f37c8b976a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2d2da60c63b67174add32f06e8d54c3a0c5cd9cf\",\n                            \"lessThan\": \"401f6a5b338d05bb1069ad814d9f77e3c367854f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2d2da60c63b67174add32f06e8d54c3a0c5cd9cf\",\n                            \"lessThan\": \"81fd7654a8429718adfcb2a7e03496077f547ed0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2d2da60c63b67174add32f06e8d54c3a0c5cd9cf\",\n                            \"lessThan\": \"89a15a50f84d32d4b99db86f957427fcbe20a99a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2d2da60c63b67174add32f06e8d54c3a0c5cd9cf\",\n                            \"lessThan\": \"ebcbd2523a8524c3d24e111cdbed8e271d910269\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2d2da60c63b67174add32f06e8d54c3a0c5cd9cf\",\n                            \"lessThan\": \"d395c30d570ca6168f0297b191709927d1258273\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2d2da60c63b67174add32f06e8d54c3a0c5cd9cf\",\n                            \"lessThan\": \"87831b92112c81db251d46756d65daa4f91af6a2\",\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                        \"net/sunrpc/auth_gss/auth_gss.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2.6.15\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.6.15\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.270\",\n                            \"lessThanOrEqual\": \"5.10.*\",\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:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/3691c4b3488d8ca046b9941e5be30c626dbbbb50","https://git.kernel.org/stable/c/85fa6b12e8f439739ac36ef2aad925f37c8b976a","https://git.kernel.org/stable/c/401f6a5b338d05bb1069ad814d9f77e3c367854f","https://git.kernel.org/stable/c/81fd7654a8429718adfcb2a7e03496077f547ed0","https://git.kernel.org/stable/c/89a15a50f84d32d4b99db86f957427fcbe20a99a","https://git.kernel.org/stable/c/ebcbd2523a8524c3d24e111cdbed8e271d910269","https://git.kernel.org/stable/c/d395c30d570ca6168f0297b191709927d1258273","https://git.kernel.org/stable/c/87831b92112c81db251d46756d65daa4f91af6a2"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89541","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89541","identifiers":["CVE-2026-89541"]},"retained":false,"historicalAffected":[]}],"coverage":[]}