{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-31610", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.122Z", "datePublished": "2026-04-24T14:42:31.471Z", "dateUpdated": "2026-05-11T22:12:08.314Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T22:12:08.314Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix mechToken leak when SPNEGO decode fails after token alloc\n\nThe kernel ASN.1 BER decoder calls action callbacks incrementally as it\nwalks the input. When ksmbd_decode_negTokenInit() reaches the mechToken\n[2] OCTET STRING element, ksmbd_neg_token_alloc() allocates\nconn->mechToken immediately via kmemdup_nul(). If a later element in\nthe same blob is malformed, then the decoder will return nonzero after\nthe allocation is already live. This could happen if mechListMIC [3]\noverrunse the enclosing SEQUENCE.\n\ndecode_negotiation_token() then sets conn->use_spnego = false because\nboth the negTokenInit and negTokenTarg grammars failed. The cleanup at\nthe bottom of smb2_sess_setup() is gated on use_spnego:\n\n\tif (conn->use_spnego && conn->mechToken) {\n\t\tkfree(conn->mechToken);\n\t\tconn->mechToken = NULL;\n\t}\n\nso the kfree is skipped, causing the mechToken to never be freed.\n\nThis codepath is reachable pre-authentication, so untrusted clients can\ncause slow memory leaks on a server without even being properly\nauthenticated.\n\nFix this up by not checking check for use_spnego, as it's not required,\nso the memory will always be properly freed. At the same time, always\nfree the memory in ksmbd_conn_free() incase some other failure path\nforgot to free it."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/connection.c", "fs/smb/server/smb2pdu.c"], "versions": [{"version": "fad4161b5cd01a24202234976ebbb133f7adc0b5", "lessThan": "745a535461bbb90a56d9357573c9f97a5c12abe1", "status": "affected", "versionType": "git"}, {"version": "fad4161b5cd01a24202234976ebbb133f7adc0b5", "lessThan": "dd577cb55588ec3fbc66af3621280306601c4192", "status": "affected", "versionType": "git"}, {"version": "fad4161b5cd01a24202234976ebbb133f7adc0b5", "lessThan": "dd53414e301beb915fe672dc4c4a51bafb917604", "status": "affected", "versionType": "git"}, {"version": "fad4161b5cd01a24202234976ebbb133f7adc0b5", "lessThan": "269c800a7a7e363459291885b35f7bc72e231ed6", "status": "affected", "versionType": "git"}, {"version": "fad4161b5cd01a24202234976ebbb133f7adc0b5", "lessThan": "6c8c44e6553b9f072f62d9875e567766eb293162", "status": "affected", "versionType": "git"}, {"version": "fad4161b5cd01a24202234976ebbb133f7adc0b5", "lessThan": "ad0057fb91218914d6c98268718ceb9d59b388e1", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/server/connection.c", "fs/smb/server/smb2pdu.c"], "versions": [{"version": "5.15", "status": "affected"}, {"version": "0", "lessThan": "5.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.136", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.83", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.24", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19.14", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.1", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1-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": "5.15", "versionEndExcluding": "6.6.136"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.83"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.18.24"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.19.14"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.0.1"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.1-rc1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/745a535461bbb90a56d9357573c9f97a5c12abe1"}, {"url": "https://git.kernel.org/stable/c/dd577cb55588ec3fbc66af3621280306601c4192"}, {"url": "https://git.kernel.org/stable/c/dd53414e301beb915fe672dc4c4a51bafb917604"}, {"url": "https://git.kernel.org/stable/c/269c800a7a7e363459291885b35f7bc72e231ed6"}, {"url": "https://git.kernel.org/stable/c/6c8c44e6553b9f072f62d9875e567766eb293162"}, {"url": "https://git.kernel.org/stable/c/ad0057fb91218914d6c98268718ceb9d59b388e1"}], "title": "ksmbd: fix mechToken leak when SPNEGO decode fails after token alloc", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"bugzilla": {"description": "kernel: ksmbd: fix mechToken leak when SPNEGO decode fails after token alloc", "id": "2461443", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2461443"}, "csaw": false, "cwe": "CWE-772", "details": ["A flaw was found in ksmbd, a component of the Linux kernel. A remote, unauthenticated attacker could exploit a flaw in the SPNEGO (Simple and Protected GSSAPI Negotiation Mechanism) decode process. This could lead to a memory leak, potentially causing a Denial of Service (DoS) on the affected system."], "name": "CVE-2026-31610", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-04-24T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-31610\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-31610\nhttps://lore.kernel.org/linux-cve-announce/2026042421-CVE-2026-31610-40ea@gregkh/T"]}

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