{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89541", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.721Z", "datePublished": "2026-09-11T19:44:18.188Z", "dateUpdated": "2026-10-19T08:48:32.929Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:48:32.929Z" }, "descriptions": [ { "lang": "en", "value": "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\")." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - gss_unwrap_resp_priv() runs in the Linux NFS/SUNRPC client while decoding RPCSEC_GSS privacy (krb5p) replies; a malicious or compromised NFS server supplies the crafted opaque_len and wrap token over the existing TCP/UDP/RDMA RPC connection.\nAC:L - The attacker fully controls the reply, including opaque_len and the cleartext RFC 4121 header, and a single response can make offset+opaque_len wrap in u32 or fall below GSS_KRB5_TOK_HDR_LEN; no race or layout beyond the attacker’s control is required.\nPR:N - The attacker is the remote RPC/NFS peer that already holds the GSS session keys needed to pass gss_validate(); no local account, user namespace, or capability on the victim client is required.\nUI:N - Once a krb5p NFS mount or other SUNRPC GSS-privacy client is already in use, normal client RPCs elicit replies the attacker can craft; no extra victim action is needed at attack time.\nS:U - Out-of-bounds reads, rotate/decrypt memory corruption, and crashes stay inside the victim kernel’s SUNRPC client and do not cross a VM, IOMMU, or other security-authority boundary.\nC:H - A short or wrapped opaque_len makes gss_krb5_unwrap_v2() read past the token at ptr+4/ptr+6 and feeds rotate_left()/decrypt with wrapped lengths, disclosing adjacent kernel memory; unwrap cleanup can also memmove nearly UINT_MAX bytes.\nI:H - The same wrapped lengths drive rotate_left() writes, CBC/AEAD decrypt over an unbounded xdr subsegment (xdr_buf_subsegment’s error is ignored), and gss_krb5_unwrap_v2()’s unsigned movelen underflow into a near-4GiB memmove, enabling kernel memory corruption.\nA:H - rotate_left() can divide-by-zero on a zero-length subbuffer, spin in a multi-gigabyte kernel loop on a wrapped subsegment, or oops/panic on the huge memmove or out-of-bounds header access." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sunrpc/auth_gss/auth_gss.c" ], "versions": [ { "version": "2d2da60c63b67174add32f06e8d54c3a0c5cd9cf", "lessThan": "3691c4b3488d8ca046b9941e5be30c626dbbbb50", "status": "affected", "versionType": "git" }, { "version": "2d2da60c63b67174add32f06e8d54c3a0c5cd9cf", "lessThan": "85fa6b12e8f439739ac36ef2aad925f37c8b976a", "status": "affected", "versionType": "git" }, { "version": "2d2da60c63b67174add32f06e8d54c3a0c5cd9cf", "lessThan": "401f6a5b338d05bb1069ad814d9f77e3c367854f", "status": "affected", "versionType": "git" }, { "version": "2d2da60c63b67174add32f06e8d54c3a0c5cd9cf", "lessThan": "81fd7654a8429718adfcb2a7e03496077f547ed0", "status": "affected", "versionType": "git" }, { "version": "2d2da60c63b67174add32f06e8d54c3a0c5cd9cf", "lessThan": "89a15a50f84d32d4b99db86f957427fcbe20a99a", "status": "affected", "versionType": "git" }, { "version": "2d2da60c63b67174add32f06e8d54c3a0c5cd9cf", "lessThan": "ebcbd2523a8524c3d24e111cdbed8e271d910269", "status": "affected", "versionType": "git" }, { "version": "2d2da60c63b67174add32f06e8d54c3a0c5cd9cf", "lessThan": "d395c30d570ca6168f0297b191709927d1258273", "status": "affected", "versionType": "git" }, { "version": "2d2da60c63b67174add32f06e8d54c3a0c5cd9cf", "lessThan": "87831b92112c81db251d46756d65daa4f91af6a2", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sunrpc/auth_gss/auth_gss.c" ], "versions": [ { "version": "2.6.15", "status": "affected" }, { "version": "0", "lessThan": "2.6.15", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.15", "versionEndExcluding": "5.10.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.15", "versionEndExcluding": "5.15.221" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.15", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.15", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.15", "versionEndExcluding": "6.12.109" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.15", "versionEndExcluding": "6.18.50" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.15", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.15", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/3691c4b3488d8ca046b9941e5be30c626dbbbb50" }, { "url": "https://git.kernel.org/stable/c/85fa6b12e8f439739ac36ef2aad925f37c8b976a" }, { "url": "https://git.kernel.org/stable/c/401f6a5b338d05bb1069ad814d9f77e3c367854f" }, { "url": "https://git.kernel.org/stable/c/81fd7654a8429718adfcb2a7e03496077f547ed0" }, { "url": "https://git.kernel.org/stable/c/89a15a50f84d32d4b99db86f957427fcbe20a99a" }, { "url": "https://git.kernel.org/stable/c/ebcbd2523a8524c3d24e111cdbed8e271d910269" }, { "url": "https://git.kernel.org/stable/c/d395c30d570ca6168f0297b191709927d1258273" }, { "url": "https://git.kernel.org/stable/c/87831b92112c81db251d46756d65daa4f91af6a2" } ], "title": "SUNRPC: harden gss_unwrap_resp_priv length checks", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-89541", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:23:27.526748Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:42.189Z" } } ] } }