CVE-2026-53176
Description
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 6.12.94-1 |
| sid | Fixed | 7.0.13-1 |
| forky | Affected | — |
| bullseye | Affected | — |
| bookworm | Affected | — |
References
- https://git.kernel.org/stable/c/75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefb
- https://git.kernel.org/stable/c/e8a013c0c3ca2f6708341a56612a3f6d6921620a
- https://git.kernel.org/stable/c/bd22740d7f14cb1c0289444cfd2c8d2938667c1d
- https://git.kernel.org/stable/c/c1234229399f4af12c553b1b0ffd978eeba65548
- https://git.kernel.org/stable/c/c5584e089b5af7b3bf8bd5e8ca0560cbf32b0a47
- https://git.kernel.org/stable/c/df422fd273c96c2ee5beb80fc21adc8c70c29260
- https://git.kernel.org/stable/c/1ca40b243277c9e88be5e00bd3e083f71aefb93e
- https://git.kernel.org/stable/c/29e7b925ae6df64894e82ab6419994dc25580a8a
- https://security-tracker.debian.org/tracker/CVE-2026-53176
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.