CVE-2026-53176
In the Linux kernel, the following vulnerability has been resolved:
IB/isert: Reject login PDUs shorter than ISERHEADERSLEN
In drivers/infiniband/ulp/isert/ibisert.c, isertloginrecvdone()
computes the login request payload length as wc->byte_len minus
ISERHEADERSLEN with no lower bound, and loginreqlen is a signed int.
A remote iSER initiator can post a login Send work request carrying
fewer than ISERHEADERSLEN (76) bytes, so the subtraction underflows
and loginreqlen becomes negative.
isertrxlogin_req() then reads that negative length back into a signed
int, takes size = min(rxbuflen, MAXKEYVALUEPAIRS), 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 ISERHEADERSLEN before the
subtraction, mirroring the existing early return on a failed work
completion, so loginreqlen can never go negative. The upper bound was
already safe: a posted login buffer cannot deliver more than
ISERRXPAYLOAD_SIZE, so the difference stays at or below
MAXKEYVALUE_PAIRS and the existing min() clamps it; only the missing
lower bound needs to be added.
Package Versions Affected
Automatically patch vulnerabilities without upgrading
CVSS Version
Related Resources
References
https://git.kernel.org/stable/c/1ca40b243277c9e88be5e00bd3e083f71aefb93e, https://git.kernel.org/stable/c/29e7b925ae6df64894e82ab6419994dc25580a8a, https://git.kernel.org/stable/c/75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefb, 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/e8a013c0c3ca2f6708341a56612a3f6d6921620a, https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53176.json, https://access.redhat.com/security/cve/CVE-2026-53176, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53176.json, https://nvd.nist.gov/vuln/detail/CVE-2026-53176, https://bugzilla.redhat.com/show_bug.cgi?id=2492741, https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git