{"id":"CVE-2026-63888","revision":null,"records":[{"revision":"da27b91a6a8545aca4cf9aeb601361b4","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-63888","aliases":[],"title":"scsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: target: iscsi: Fix CRC overread and double-free in iscsit_handle_text_cmd()\n\nTwo latent bugs in the Text-phase handler, both present since the\noriginal LIO integration in commit e48354ce078c (\"iscsi-target: Add\niSCSI fabric support for target v4.1\"):\n\n1) DataDigest CRC buffer overread (4 bytes past text_in).\n\n text_in is kzalloc()'d at ALIGN(payload_length, 4). rx_size is then\n incremented by ISCSI_CRC_LEN to make room for the received DataDigest\n in the iovec, but the same (now-bumped) rx_size is passed as the\n buffer length to iscsit_crc_buf():\n\n if (conn->conn_ops->DataDigest) {\n ...\n rx_size += ISCSI_CRC_LEN;\n }\n ...\n if (conn->conn_ops->DataDigest) {\n data_crc = iscsit_crc_buf(text_in, rx_size, 0, NULL);\n\n iscsit_crc_buf() walks rx_size bytes of text_in with crc32c(), so\n when DataDigest is negotiated it reads 4 bytes past the end of the\n text_in allocation. KASAN reproduces this directly on the unpatched\n mainline tree as slab-out-of-bounds in crc32c() called from the Text\n PDU path. The OOB bytes feed crc32c() and are then compared against\n the initiator-supplied checksum, so the value does not flow back to\n the attacker, but the kernel does read past the buffer on every Text\n PDU with DataDigest=CRC32C.\n\n Fix by passing the actual padded payload length\n (ALIGN(payload_length, 4)) that was used for the kzalloc().\n\n2) Stale cmd->text_in_ptr re-free (double-free) on ERL>0 bad DataDigest\n drop.\n\n On DataDigest mismatch with ErrorRecoveryLevel > 0 the handler\n silently drops the PDU and lets the initiator plug the CmdSN gap:\n\n kfree(text_in);\n return 0;\n\n cmd->text_in_ptr still points at the freed buffer. The next Text\n Request on the same ITT re-enters iscsit_setup_text_cmd(), which\n unconditionally does\n\n kfree(cmd->text_in_ptr);\n cmd->text_in_ptr = NULL;\n\n freeing the same pointer a second time. Session teardown via\n iscsit_release_cmd() has the same shape and hits the same double-free\n if the connection is dropped before a second Text Request arrives.\n\n On an unmodified mainline tree the bug-1 CRC overread fires first on\n the initial valid Text Request and perturbs the subsequent state, so\n #4 was isolated by building a kernel with only the bug-1 hunk of this\n patch applied plus temporary printk() observability around the three\n relevant kfree() sites. The observability prints are not part of\n this patch. On that build, a three-PDU Text Request sequence after\n login produces two back-to-back splats:\n\n BUG: KASAN: double-free in iscsit_setup_text_cmd+0x??\n BUG: KASAN: double-free in iscsit_release_cmd+0x??\n\n showing the same pointer freed in the ERL>0 drop path and again in\n iscsit_setup_text_cmd() (next Text Request on the same ITT) and once\n more in iscsit_release_cmd() (session teardown). On distro kernels\n with CONFIG_SLAB_FREELIST_HARDENED=y (default) the double-free\n becomes a remote kernel BUG(); on non-hardened kernels it corrupts\n the slab freelist.\n\n Fix by clearing cmd->text_in_ptr after the kfree() in the ERL>0 drop\n path. With both hunks applied #4 is directly observable on the stock\n tree without observability printks; fixing bug-1 alone would mask #4\n less, not more, so the hunks are submitted together.\n\nBoth fixes are one-liners. The Text PDU state machine is unchanged and\nthe wire protocol is unaffected.","state":0,"publishedAt":"2026-07-19T14:55:00.803+00:00","modifiedAt":"2026-10-19T20:17:54.825+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 \"drivers/target/iscsi/iscsi_target.c\"\n ],\n \"versions\": [\n {\n \"version\": \"e48354ce078c079996f89d715dfa44814b4eba01\",\n \"lessThan\": \"f7948af0dd03de84079dcd4dc215a69fd6fbb95d\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e48354ce078c079996f89d715dfa44814b4eba01\",\n \"lessThan\": \"badf178b76b0690851df00f4ca9cf2eb8eb0f963\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e48354ce078c079996f89d715dfa44814b4eba01\",\n \"lessThan\": \"6e22a1cdcc8277af4acc43710577157b77a02c5d\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e48354ce078c079996f89d715dfa44814b4eba01\",\n \"lessThan\": \"d3e9b79aa794f7a23e82de4d710e7d2df610e349\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e48354ce078c079996f89d715dfa44814b4eba01\",\n \"lessThan\": \"ec9f19d52074a191ed1756ed4a7d39fff1a2085c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e48354ce078c079996f89d715dfa44814b4eba01\",\n \"lessThan\": \"89c81d1228c00fa6dd91de6c1c5aa1ef8a7875e3\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e48354ce078c079996f89d715dfa44814b4eba01\",\n \"lessThan\": \"5118ea225fe63b44207ba88047e4866e1ea43812\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"e48354ce078c079996f89d715dfa44814b4eba01\",\n \"lessThan\": \"778c2ab142c625a8a8afa570e0f9b7873f445d99\",\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 \"drivers/target/iscsi/iscsi_target.c\"\n ],\n \"versions\": [\n {\n \"version\": \"3.1\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"3.1\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.259\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.210\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.176\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.143\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.93\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.35\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.0.12\",\n \"lessThanOrEqual\": \"7.0.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.1\",\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/f7948af0dd03de84079dcd4dc215a69fd6fbb95d","https://git.kernel.org/stable/c/badf178b76b0690851df00f4ca9cf2eb8eb0f963","https://git.kernel.org/stable/c/6e22a1cdcc8277af4acc43710577157b77a02c5d","https://git.kernel.org/stable/c/d3e9b79aa794f7a23e82de4d710e7d2df610e349","https://git.kernel.org/stable/c/ec9f19d52074a191ed1756ed4a7d39fff1a2085c","https://git.kernel.org/stable/c/89c81d1228c00fa6dd91de6c1c5aa1ef8a7875e3","https://git.kernel.org/stable/c/5118ea225fe63b44207ba88047e4866e1ea43812","https://git.kernel.org/stable/c/778c2ab142c625a8a8afa570e0f9b7873f445d99"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63888","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-63888","identifiers":["CVE-2026-63888"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. Missing entries do not establish absence of exploitation.","generation":"2026-11-08T19:47:20.1649891+00:00","complete":true,"records":1769,"lastAttemptAt":"2026-11-08T19:47:20.1649891+00:00","lastSuccessAt":"2026-11-08T19:47:20.3943637+00:00","error":null,"lastVerifiedAt":"2026-11-08T19:47:20.3943658+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"cve-program","scope":"Official CVE Program baseline and cumulative hourly delta; all vendors, published and rejected records","generation":"cve-eaa64dac63caa79c8d4905619258c41c51b39e461b996124e1a21b5e85e7e738-5ed072895efd00dfc9298eaa4ea0dc8e51b29da4254bc61a9f28835ec1fa6ea6","complete":true,"records":421260,"lastAttemptAt":"2026-11-08T19:47:19.7023073+00:00","lastSuccessAt":"2026-11-08T19:47:19.6080199+00:00","error":null,"lastVerifiedAt":"2026-11-08T19:47:19.7023073+00:00","snapshotPublishedAt":"2026-11-08T19:27:43+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"euvd","scope":"Rolling EUVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-f1b70ba09149408c9b3f93f80725b8b9","complete":true,"records":13654,"lastAttemptAt":"2026-11-08T19:48:04.0257169+00:00","lastSuccessAt":"2026-11-08T19:48:04.022+00:00","error":null,"lastVerifiedAt":"2026-11-08T19:48:04.022+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-08T19:47:20.1649891+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-08T19:47:20.1649891+00:00","lastSuccessAt":"2026-11-08T19:47:20.3951142+00:00","error":null,"lastVerifiedAt":"2026-11-08T19:47:20.3951146+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-3b79c659b4ac42b2801e63ff6ff3a882","complete":false,"records":13666,"lastAttemptAt":"2026-11-08T19:47:46.1695591+00:00","lastSuccessAt":"2026-11-08T19:47:46.166+00:00","error":null,"lastVerifiedAt":"2026-11-08T19:47:46.166+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13206,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-980593e6977a6d1b4fb1eed5a1ffe88a468736f89f0a06f710924ad59132c023","complete":true,"records":9914,"lastAttemptAt":"2026-11-08T19:47:20.0165357+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-08T19:47:20.0165357+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-fde804134ecdda0ddd5ff5c26ee1fff5a6fa659311f7ef2e51c6ad54964db0e2","complete":true,"records":1971,"lastAttemptAt":"2026-11-08T19:47:19.7560084+00:00","lastSuccessAt":"2026-11-06T19:03:17.0399903+00:00","error":null,"lastVerifiedAt":"2026-11-08T19:47:19.7560084+00:00","snapshotPublishedAt":"2026-11-06T18:17:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-964c14035e6f0f6478b2870fad6a7ef9f6045876d4a12af2c2e514521e54b6af","complete":true,"records":3055,"lastAttemptAt":"2026-11-08T19:47:20.1181272+00:00","lastSuccessAt":"2026-11-08T11:07:12.1927025+00:00","error":null,"lastVerifiedAt":"2026-11-08T19:47:20.1181272+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-f8647d7ba64b1ba0dfdc7130944766d5b36d5b77d18fff0c79e651a4cff3c2b9","complete":true,"records":231293,"lastAttemptAt":"2026-11-08T19:47:19.9161497+00:00","lastSuccessAt":"2026-11-08T11:06:56.2918717+00:00","error":null,"lastVerifiedAt":"2026-11-08T19:47:19.9161497+00:00","snapshotPublishedAt":"2026-11-08T11:02:50+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}