{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89538", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.721Z", "datePublished": "2026-09-11T19:44:15.953Z", "dateUpdated": "2026-09-11T19:44:15.953Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-11T19:44:15.953Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: Reject krb5 v2 wrap tokens with oversized ec field\n\ngss_krb5_unwrap_v2() sets buf->len to a logical\nlength, which can be much smaller than head[0].iov_len\n(the allocated receive-page capacity). It then calls\nxdr_buf_trim() with a trim length derived from the 16-bit\n\"extra count\" (ec) field in the Kerberos v2 token header.\n\nThe ec field is authenticated by the post-decrypt memcmp()\nagainst the encrypted header copy, so a randomly-mutated\nvalue is rejected. However, any peer holding a valid GSS\ncontext can legitimately encrypt a token whose ec exceeds\nthe plaintext length. Per RFC 4121, such a token is\nstructurally malformed.\n\nAlthough xdr_buf_trim() now clamps the buf->len subtraction\nto avoid unsigned underflow, the buffer is still left in a\nsemantically invalid state (zero length, inconsistent iov\nlengths) when ec is oversized.\n\nReject these tokens before calling xdr_buf_trim(), giving\ncallers a well-defined GSS_S_DEFECTIVE_TOKEN error and\nkeeping the xdr_buf internally consistent. The wrapped blob\nbegins at a nonzero offset -- both callers pass len as\noffset + opaque_len -- so buf->len still counts the offset\nbytes that precede the blob. Compare the trim length\nagainst the remaining wrapped segment, buf->len - offset,\nrather than the whole buffer; comparing against buf->len\nalone leaves an offset-wide window in which an oversized ec\npasses the test and xdr_buf_trim() cuts into the bytes ahead\nof the blob."}], "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/gss_krb5_wrap.c"], "versions": [{"version": "cf4c024b908353fcc48309374d39e3399d67dfd1", "lessThan": "dfcd81ab45613d45996fbf483d4ef54b0ec90ab9", "status": "affected", "versionType": "git"}, {"version": "cf4c024b908353fcc48309374d39e3399d67dfd1", "lessThan": "1f9856af065b6158271687e9788407b9573fd16f", "status": "affected", "versionType": "git"}, {"version": "cf4c024b908353fcc48309374d39e3399d67dfd1", "lessThan": "880effc943ed82d6811f272ed3307c222b40f4d6", "status": "affected", "versionType": "git"}, {"version": "cf4c024b908353fcc48309374d39e3399d67dfd1", "lessThan": "ad484748eec0a66eac0f13ab53b3fbedb7333c91", "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/gss_krb5_wrap.c"], "versions": [{"version": "3.13", "status": "affected"}, {"version": "0", "lessThan": "3.13", "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-rc1", "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": "3.13", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "7.3-rc1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/dfcd81ab45613d45996fbf483d4ef54b0ec90ab9"}, {"url": "https://git.kernel.org/stable/c/1f9856af065b6158271687e9788407b9573fd16f"}, {"url": "https://git.kernel.org/stable/c/880effc943ed82d6811f272ed3307c222b40f4d6"}, {"url": "https://git.kernel.org/stable/c/ad484748eec0a66eac0f13ab53b3fbedb7333c91"}], "title": "SUNRPC: Reject krb5 v2 wrap tokens with oversized ec field", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/sunrpc/auth_gss/gss_krb5_wrap.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "dfcd81ab45613d45996fbf483d4ef54b0ec90ab9", "status": "affected", "version": "cf4c024b908353fcc48309374d39e3399d67dfd1", "versionType": "git"}, {"lessThan": "1f9856af065b6158271687e9788407b9573fd16f", "status": "affected", "version": "cf4c024b908353fcc48309374d39e3399d67dfd1", "versionType": "git"}, {"lessThan": "880effc943ed82d6811f272ed3307c222b40f4d6", "status": "affected", "version": "cf4c024b908353fcc48309374d39e3399d67dfd1", "versionType": "git"}, {"lessThan": "ad484748eec0a66eac0f13ab53b3fbedb7333c91", "status": "affected", "version": "cf4c024b908353fcc48309374d39e3399d67dfd1", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/sunrpc/auth_gss/gss_krb5_wrap.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "3.13"}, {"lessThan": "3.13", "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"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: Reject krb5 v2 wrap tokens with oversized ec field\n\ngss_krb5_unwrap_v2() sets buf->len to a logical\nlength, which can be much smaller than head[0].iov_len\n(the allocated receive-page capacity). It then calls\nxdr_buf_trim() with a trim length derived from the 16-bit\n\"extra count\" (ec) field in the Kerberos v2 token header.\n\nThe ec field is authenticated by the post-decrypt memcmp()\nagainst the encrypted header copy, so a randomly-mutated\nvalue is rejected. However, any peer holding a valid GSS\ncontext can legitimately encrypt a token whose ec exceeds\nthe plaintext length. Per RFC 4121, such a token is\nstructurally malformed.\n\nAlthough xdr_buf_trim() now clamps the buf->len subtraction\nto avoid unsigned underflow, the buffer is still left in a\nsemantically invalid state (zero length, inconsistent iov\nlengths) when ec is oversized.\n\nReject these tokens before calling xdr_buf_trim(), giving\ncallers a well-defined GSS_S_DEFECTIVE_TOKEN error and\nkeeping the xdr_buf internally consistent. The wrapped blob\nbegins at a nonzero offset -- both callers pass len as\noffset + opaque_len -- so buf->len still counts the offset\nbytes that precede the blob. Compare the trim length\nagainst the remaining wrapped segment, buf->len - offset,\nrather than the whole buffer; comparing against buf->len\nalone leaves an offset-wide window in which an oversized ec\npasses the test and xdr_buf_trim() cuts into the bytes ahead\nof the blob."}], "id": "CVE-2026-89538", "lastModified": "2026-09-11T20:19:36.850", "metrics": {}, "published": "2026-09-11T20:19:36.850", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1f9856af065b6158271687e9788407b9573fd16f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/880effc943ed82d6811f272ed3307c222b40f4d6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ad484748eec0a66eac0f13ab53b3fbedb7333c91"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/dfcd81ab45613d45996fbf483d4ef54b0ec90ab9"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: SUNRPC vulnerability in Kerberos v2 token processing", "id": "2532114", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532114"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.3", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-131", "details": ["A flaw was found in the Linux kernel's Server Unix Remote Procedure Call (SUNRPC) component. A remote attacker, with a valid Generic Security Service (GSS) context, could send a specially crafted Kerberos v2 wrap token with an oversized \"extra count\" (ec) field. This improper handling of malformed tokens could lead to the buffer being left in a semantically invalid state, potentially causing a denial of service or other unpredictable behavior within the system."], "name": "CVE-2026-89538", "public_date": "2026-09-11T19:44:15Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89538\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89538\nhttps://git.kernel.org/stable/c/1f9856af065b6158271687e9788407b9573fd16f\nhttps://git.kernel.org/stable/c/880effc943ed82d6811f272ed3307c222b40f4d6\nhttps://git.kernel.org/stable/c/ad484748eec0a66eac0f13ab53b3fbedb7333c91\nhttps://git.kernel.org/stable/c/dfcd81ab45613d45996fbf483d4ef54b0ec90ab9"], "threat_severity": "Important"}

{}