{"api_version":"1","generated_at":"2026-09-12T05:51:52+00:00","cve":"CVE-2026-89550","urls":{"html":"https://cve.report/CVE-2026-89550","api":"https://cve.report/api/cve/CVE-2026-89550.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89550","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89550"},"summary":{"title":"SUNRPC: svcauth_gss: enforce krb5 token minimum length","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: svcauth_gss: enforce krb5 token minimum length\n\nsvcauth_gss_unwrap_priv() validates only an upper bound on the\nwire-supplied opaque length before handing the buffer to\ngss_unwrap():\n\n    if (len > xdr_stream_remaining(xdr))\n            goto unwrap_failed;\n    offset = xdr_stream_pos(xdr);\n    ...\n    maj_stat = gss_unwrap(ctx, offset, offset + len, buf);\n\nThe wire value `len` flows unchanged as the upper bound into the\nkrb5 unwrap path, so a len in [0, 16] passes this check and is\nhanded to gss_unwrap(). For a krb5 v2 context that lands in\ngss_krb5_unwrap_v2(), which reads the 16-byte RFC 4121 token\nheader fields at ptr+4 and ptr+6 and then calls rotate_left()\nbefore any integrity check. With a sub-header length the header\nreads run past the token, and _rotate_left()'s `shift %= buf->len`\npath can divide by zero when buf->len has been driven to zero by\nthe truncated token. A header-only token (len == 16) is equally\ninvalid: with a non-zero RRC field and the opaque blob ending at\nthe XDR buffer boundary, rotate_left() builds a zero-length\nsubbuffer, reaching the same division.\n\nReject the token at the server entry point before it reaches the\nkrb5 unwrap core. A valid sealed RFC 4121 token must contain\nthe 16-byte header plus at least some encrypted payload.\n\nFix by adding a minimum-length check immediately after the\nexisting upper-bound check:\n\n    if (len <= GSS_KRB5_TOK_HDR_LEN)\n            goto unwrap_failed;","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:19:38","updated_at":"2026-09-11 20:19:38"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/de942dd8c2c8358bcad04ce44271954c48924423","name":"https://git.kernel.org/stable/c/de942dd8c2c8358bcad04ce44271954c48924423","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dd6afc6cab8c5d387d1ed2f069562ef7bdadd651","name":"https://git.kernel.org/stable/c/dd6afc6cab8c5d387d1ed2f069562ef7bdadd651","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a919c5c88769cf8fb3ec071e6078d830bf512489","name":"https://git.kernel.org/stable/c/a919c5c88769cf8fb3ec071e6078d830bf512489","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2eed1e6a976a44015c3ee78841fe336796e2b21c","name":"https://git.kernel.org/stable/c/2eed1e6a976a44015c3ee78841fe336796e2b21c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89550","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89550","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7c9fdcfb1b64c47ed618c103b617af3f86e1239c dd6afc6cab8c5d387d1ed2f069562ef7bdadd651 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7c9fdcfb1b64c47ed618c103b617af3f86e1239c de942dd8c2c8358bcad04ce44271954c48924423 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7c9fdcfb1b64c47ed618c103b617af3f86e1239c 2eed1e6a976a44015c3ee78841fe336796e2b21c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7c9fdcfb1b64c47ed618c103b617af3f86e1239c a919c5c88769cf8fb3ec071e6078d830bf512489 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2.6.18","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 2.6.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.109 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.50 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/sunrpc/auth_gss/svcauth_gss.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"dd6afc6cab8c5d387d1ed2f069562ef7bdadd651","status":"affected","version":"7c9fdcfb1b64c47ed618c103b617af3f86e1239c","versionType":"git"},{"lessThan":"de942dd8c2c8358bcad04ce44271954c48924423","status":"affected","version":"7c9fdcfb1b64c47ed618c103b617af3f86e1239c","versionType":"git"},{"lessThan":"2eed1e6a976a44015c3ee78841fe336796e2b21c","status":"affected","version":"7c9fdcfb1b64c47ed618c103b617af3f86e1239c","versionType":"git"},{"lessThan":"a919c5c88769cf8fb3ec071e6078d830bf512489","status":"affected","version":"7c9fdcfb1b64c47ed618c103b617af3f86e1239c","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/sunrpc/auth_gss/svcauth_gss.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.18"},{"lessThan":"2.6.18","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.109","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.50","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.109","versionStartIncluding":"2.6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.50","versionStartIncluding":"2.6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"2.6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"2.6.18","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: svcauth_gss: enforce krb5 token minimum length\n\nsvcauth_gss_unwrap_priv() validates only an upper bound on the\nwire-supplied opaque length before handing the buffer to\ngss_unwrap():\n\n    if (len > xdr_stream_remaining(xdr))\n            goto unwrap_failed;\n    offset = xdr_stream_pos(xdr);\n    ...\n    maj_stat = gss_unwrap(ctx, offset, offset + len, buf);\n\nThe wire value `len` flows unchanged as the upper bound into the\nkrb5 unwrap path, so a len in [0, 16] passes this check and is\nhanded to gss_unwrap(). For a krb5 v2 context that lands in\ngss_krb5_unwrap_v2(), which reads the 16-byte RFC 4121 token\nheader fields at ptr+4 and ptr+6 and then calls rotate_left()\nbefore any integrity check. With a sub-header length the header\nreads run past the token, and _rotate_left()'s `shift %= buf->len`\npath can divide by zero when buf->len has been driven to zero by\nthe truncated token. A header-only token (len == 16) is equally\ninvalid: with a non-zero RRC field and the opaque blob ending at\nthe XDR buffer boundary, rotate_left() builds a zero-length\nsubbuffer, reaching the same division.\n\nReject the token at the server entry point before it reaches the\nkrb5 unwrap core. A valid sealed RFC 4121 token must contain\nthe 16-byte header plus at least some encrypted payload.\n\nFix by adding a minimum-length check immediately after the\nexisting upper-bound check:\n\n    if (len <= GSS_KRB5_TOK_HDR_LEN)\n            goto unwrap_failed;"}],"providerMetadata":{"dateUpdated":"2026-09-11T19:44:24.572Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/dd6afc6cab8c5d387d1ed2f069562ef7bdadd651"},{"url":"https://git.kernel.org/stable/c/de942dd8c2c8358bcad04ce44271954c48924423"},{"url":"https://git.kernel.org/stable/c/2eed1e6a976a44015c3ee78841fe336796e2b21c"},{"url":"https://git.kernel.org/stable/c/a919c5c88769cf8fb3ec071e6078d830bf512489"}],"title":"SUNRPC: svcauth_gss: enforce krb5 token minimum length","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89550","datePublished":"2026-09-11T19:44:24.572Z","dateReserved":"2026-09-11T19:38:34.723Z","dateUpdated":"2026-09-11T19:44:24.572Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:19:38","lastModifiedDate":"2026-09-11 20:19:38","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89550","Ordinal":"1","Title":"SUNRPC: svcauth_gss: enforce krb5 token minimum length","CVE":"CVE-2026-89550","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89550","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: svcauth_gss: enforce krb5 token minimum length\n\nsvcauth_gss_unwrap_priv() validates only an upper bound on the\nwire-supplied opaque length before handing the buffer to\ngss_unwrap():\n\n    if (len > xdr_stream_remaining(xdr))\n            goto unwrap_failed;\n    offset = xdr_stream_pos(xdr);\n    ...\n    maj_stat = gss_unwrap(ctx, offset, offset + len, buf);\n\nThe wire value `len` flows unchanged as the upper bound into the\nkrb5 unwrap path, so a len in [0, 16] passes this check and is\nhanded to gss_unwrap(). For a krb5 v2 context that lands in\ngss_krb5_unwrap_v2(), which reads the 16-byte RFC 4121 token\nheader fields at ptr+4 and ptr+6 and then calls rotate_left()\nbefore any integrity check. With a sub-header length the header\nreads run past the token, and _rotate_left()'s `shift %= buf->len`\npath can divide by zero when buf->len has been driven to zero by\nthe truncated token. A header-only token (len == 16) is equally\ninvalid: with a non-zero RRC field and the opaque blob ending at\nthe XDR buffer boundary, rotate_left() builds a zero-length\nsubbuffer, reaching the same division.\n\nReject the token at the server entry point before it reaches the\nkrb5 unwrap core. A valid sealed RFC 4121 token must contain\nthe 16-byte header plus at least some encrypted payload.\n\nFix by adding a minimum-length check immediately after the\nexisting upper-bound check:\n\n    if (len <= GSS_KRB5_TOK_HDR_LEN)\n            goto unwrap_failed;","Type":"Description","Title":"SUNRPC: svcauth_gss: enforce krb5 token minimum length"}]}}}