--- id: CVE-2026-53176 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… summary: |- 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… severity: critical cvss: 9.8 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H' cwe: - CWE-191 - CWE-839 vendor: linux product: linux_kernel affected: - 'linux_kernel >= 3.10, < 5.10.259' - 'linux_kernel >= 5.11, < 5.15.210' - 'linux_kernel >= 5.16, < 6.1.176' - 'linux_kernel >= 6.2, < 6.6.143' - 'linux_kernel >= 6.7, < 6.12.94' - 'linux_kernel >= 6.13, < 6.18.36' - 'linux_kernel >= 6.19, < 7.0.13' - linux_kernel = 7.1 patched: - linux_kernel 7.0.13 published: '2026-06-25' updated: '2026-09-18' sourceUpdated: '2026-09-18T13:18:32.900' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53176' references: - url: 'https://git.kernel.org/stable/c/1ca40b243277c9e88be5e00bd3e083f71aefb93e' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/29e7b925ae6df64894e82ab6419994dc25580a8a' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefb' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/bd22740d7f14cb1c0289444cfd2c8d2938667c1d' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/c1234229399f4af12c553b1b0ffd978eeba65548' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/c5584e089b5af7b3bf8bd5e8ca0560cbf32b0a47' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/df422fd273c96c2ee5beb80fc21adc8c70c29260' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/e8a013c0c3ca2f6708341a56612a3f6d6921620a' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://access.redhat.com/errata/RHSA-2026:68507' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:68531' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:68532' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/errata/RHSA-2026:68570' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://access.redhat.com/security/cve/CVE-2026-53176' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2492741' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53176.json label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://www.cve.org/CVERecord?id=CVE-2026-53176' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53176' - url: >- https://lore.kernel.org/linux-cve-announce/2026062553-CVE-2026-53176-c8a7@gregkh/T tags: - nvd - cve.org - csaf - vex - red-hat - score-dispute epss: 0.00761 epssPercentile: 0.53333 scores: nvd: 9.8 vendor: 6.5 cna: 9.8 ingestedAt: '2026-07-06T17:44:51.378Z' --- ## Overview 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 minus ISER_HEADERS_LEN with no lower bound, and login_req_len is a signed int. A remote iSER initiator can post a login Send work request carrying fewer than ISER_HEADERS_LEN (76) bytes, so the subtraction underflows and login_req_len becomes negative. isert_rx_login_req() then reads that negative length back into a signed int, takes size = min(rx_buflen, MAX_KEY_VALUE_PAIRS), and because the min() is signed it keeps the negative value; the value is then passed as the memcpy() length and sign-extended to a multi-gigabyte size_t. The copy into the 8192-byte login->req_buf runs far out of bounds and faults, crashing the target node. The login phase precedes iSCSI authentication, so no credentials are required to reach this path. Reject any login PDU shorter than ISER_HEADERS_LEN before the subtraction, mirroring the existing early return on a failed work completion, so login_req_len can never go negative. The upper bound was already safe: a posted login buffer cannot deliver more than ISER_RX_PAYLOAD_SIZE, so the difference stays at or below MAX_KEY_VALUE_PAIRS and the existing min() clamps it; only the missing lower bound needs to be added. ## Affected - `linux_kernel >= 3.10, < 5.10.259` - `linux_kernel >= 5.11, < 5.15.210` - `linux_kernel >= 5.16, < 6.1.176` - `linux_kernel >= 6.2, < 6.6.143` - `linux_kernel >= 6.7, < 6.12.94` - `linux_kernel >= 6.13, < 6.18.36` - `linux_kernel >= 6.19, < 7.0.13` - `linux_kernel = 7.1` ## Remediation Upgrade past the affected range: - `linux_kernel 7.0.13` ## Vendor advisories - **RHSA-2026:68507** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68507) - **RHSA-2026:68570** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68570) - **RHSA-2026:68531** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68531) - **RHSA-2026:68532** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68532) - **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9 · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53176.json)