{"id":"CVE-2026-53176","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-53176","generatedAt":"2026-10-28T09:26:27.933Z","title":"In the Linux kernel, the following vulnerability has been resolved: IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN In drivers/infiniband/ulp/isert/ib_isert.c, isert_login_recv_done() computes the login request payload length as wc->byte_len…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nIB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN\n\nIn drivers/infiniband/ulp/isert/ib_isert.c, isert_login_recv_done()\ncomputes the login request payload length as wc->byte_len minus\nISER_HEADERS_LEN with no lower bound, and login_req_len is a signed int.\nA remote iSER initiator can post a login Send work request carrying\nfewer than ISER_HEADERS_LEN (76) bytes, so the subtraction underflows\nand login_req_len becomes negative.\n\nisert_rx_login_req() then reads that negative length back into a signed\nint, takes size = min(rx_buflen, MAX_KEY_VALUE_PAIRS), and because the\nmin() is signed it keeps the negative value; the value is then passed as\nthe memcpy() length and sign-extended to a multi-gigabyte size_t. The\ncopy into the 8192-byte login->req_buf runs far out of bounds and\nfaults, crashing the target node. The login phase precedes iSCSI\nauthentication, so no credentials are required to reach this path.\n\nReject any login PDU shorter than ISER_HEADERS_LEN before the\nsubtraction, mirroring the existing early return on a failed work\ncompletion, so login_req_len can never go negative. The upper bound was\nalready safe: a posted login buffer cannot deliver more than\nISER_RX_PAYLOAD_SIZE, so the difference stays at or below\nMAX_KEY_VALUE_PAIRS and the existing min() clamps it; only the missing\nlower bound needs to be added.","published":"2026-06-25T09:16:35.000Z","lastModified":"2026-10-19T20:19:06.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-191","CWE-839"],"affected":["linux/linux kernel"],"epss":{"score":0.00761,"percentile":0.55107,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.76%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/1ca40b243277c9e88be5e00bd3e083f71aefb93e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/29e7b925ae6df64894e82ab6419994dc25580a8a","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefb","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bd22740d7f14cb1c0289444cfd2c8d2938667c1d","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c1234229399f4af12c553b1b0ffd978eeba65548","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c5584e089b5af7b3bf8bd5e8ca0560cbf32b0a47","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/df422fd273c96c2ee5beb80fc21adc8c70c29260","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e8a013c0c3ca2f6708341a56612a3f6d6921620a","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://access.redhat.com/errata/RHSA-2026:68507","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:68531","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:68532","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:68570","source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/security/cve/CVE-2026-53176","tags":["Third Party Advisory"],"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2492741","tags":["Issue Tracking","Third Party Advisory"],"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53176.json","tags":["Third Party Advisory"],"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-53176","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}