From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-53176: IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN
Date: Thu, 25 Jun 2026 09:40:24 +0100 [thread overview]
Message-ID: <2026062553-CVE-2026-53176-c8a7@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
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.
The Linux kernel CVE team has assigned CVE-2026-53176 to this issue.
Affected and fixed versions
===========================
Issue introduced in 3.10 with commit b8d26b3be8b33682cf163274ed07479a70554633 and fixed in 5.10.259 with commit 75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefb
Issue introduced in 3.10 with commit b8d26b3be8b33682cf163274ed07479a70554633 and fixed in 5.15.210 with commit e8a013c0c3ca2f6708341a56612a3f6d6921620a
Issue introduced in 3.10 with commit b8d26b3be8b33682cf163274ed07479a70554633 and fixed in 6.1.176 with commit bd22740d7f14cb1c0289444cfd2c8d2938667c1d
Issue introduced in 3.10 with commit b8d26b3be8b33682cf163274ed07479a70554633 and fixed in 6.6.143 with commit c1234229399f4af12c553b1b0ffd978eeba65548
Issue introduced in 3.10 with commit b8d26b3be8b33682cf163274ed07479a70554633 and fixed in 6.12.94 with commit c5584e089b5af7b3bf8bd5e8ca0560cbf32b0a47
Issue introduced in 3.10 with commit b8d26b3be8b33682cf163274ed07479a70554633 and fixed in 6.18.36 with commit df422fd273c96c2ee5beb80fc21adc8c70c29260
Issue introduced in 3.10 with commit b8d26b3be8b33682cf163274ed07479a70554633 and fixed in 7.0.13 with commit 1ca40b243277c9e88be5e00bd3e083f71aefb93e
Issue introduced in 3.10 with commit b8d26b3be8b33682cf163274ed07479a70554633 and fixed in 7.1 with commit 29e7b925ae6df64894e82ab6419994dc25580a8a
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2026-53176
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
drivers/infiniband/ulp/isert/ib_isert.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
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
reply other threads:[~2026-06-25 8:45 UTC|newest]
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