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CVE-2026-90414— IB/isert: reject PDUs declaring more data than was received

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，已修复如下漏洞： IB/isert：拒绝声明接收数据量超过实际接收量的 PDU 在处理每个接收到的 PDU 时，直接将其交给操作码（opcode）处理器，却从未检查 ——即主机通道适配器（HCA）实际放入接收描述符中的字节数。随后，这些处理器会从固定大小的描述符中复制相应数量的字节，其长度依据的是发起方在基头段（BHS）中声明的数据段长度（通过 派生出的 或 ）： 由于声明的长度从未与实际接收的 进行比对，发起方可以声明一个比其实际发送的字节数更大（且大于描述符容量）的数据段，从而导致接收缓

CVSS 9.1 · Critical EPSS 0.52% · P43

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux b8d26b3be8b33682cf163274ed07479a70554633< b4706722ed3ea72882b3c986a19b4a1ba66384c4 affected
b8d26b3be8b33682cf163274ed07479a70554633< bc58e9d3dc560220c57b8bdfc12af0cff1c8a43d affected
b8d26b3be8b33682cf163274ed07479a70554633< 274b1ad7e78338710864c4b4235bb1ce7e7107f9 affected
b8d26b3be8b33682cf163274ed07479a70554633< 2a6b8f88fb7ee51714a1922a039225bdcaf12855 affected
b8d26b3be8b33682cf163274ed07479a70554633< 39da0b7e1f530347d284cebcfc5b5afa90a173bf affected
b8d26b3be8b33682cf163274ed07479a70554633< cf36fa5357a2fb25776a568d13a3653da7d99bcb affected
b8d26b3be8b33682cf163274ed07479a70554633< 352dc85324b29f5c85876f2666f3158b645e3f18 affected
b8d26b3be8b33682cf163274ed07479a70554633< 957f92ea4022fb6af4618271615a2a21a7b5bef9 affected
… +10 more rows
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I. Basic Information for CVE-2026-90414

Vulnerability Information
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Vulnerability Title
IB/isert: reject PDUs declaring more data than was received
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: IB/isert: reject PDUs declaring more data than was received isert_recv_done() hands each received PDU to the opcode handlers without ever looking at wc->byte_len, the number of bytes the HCA actually placed in the receive descriptor. The handlers then copy that many bytes - the data-segment length the initiator declared in the BHS (ntoh24(hdr->dlength), via the derived unsol_data_len / imm_data_len) - out of the fixed-size descriptor: isert_handle_iscsi_dataout(): sg_copy_from_buffer(sg_start, sg_nents, isert_get_data(rx_desc), unsol_data_len); isert_handle_scsi_cmd(): sg_copy_from_buffer(cmd->se_cmd.t_data_sg, sg_nents, isert_get_data(rx_desc), imm_data_len); Because the declared length is never checked against wc->byte_len, an initiator can declare a data segment larger than the bytes it actually sent (and larger than the descriptor) and cause an out-of-bounds read of the receive buffer. Nothing upstream of isert closes this door: - __iscsit_check_dataout_hdr() bounds the inbound payload against conn_ops->MaxXmitDataSegmentLength (MXDSL) - a transmit parameter, used here for the inbound check. - iscsi_set_connection_parameters() sets ops->MaxXmitDataSegmentLength = ops->TargetRecvDataSegmentLength; and TARGETRECVDATASEGMENTLENGTH is absent from the min()-clamp list in iscsi_check_acceptor_state(), so the value the initiator declares is adopted verbatim (type range 512..16777215). The initiator effectively raises its own ceiling. - isert never clamps the negotiated value to its own fixed receive descriptor (ISER_RX_SIZE, 9216 bytes), so the target core's bound and the descriptor size are unrelated. The imm_data_len == data_len path is more than an over-read: it aliases the receive descriptor via sg_set_buf() and passes it to the backend as the data source for the SCSI WRITE, so an over-declared length causes heap contents past the descriptor to be written through the backend to the backing store. The backend is the victim of the oversized scatterlist isert hands it, not the cause; no read-back of the written bytes was demonstrated. Trigger: after login completes (full feature phase), an initiator that has declared a large TargetRecvDataSegmentLength and a FirstBurstLength that permits unsolicited/immediate data sends a PDU whose declared data-segment length exceeds what was received. With KASAN: BUG: KASAN: slab-out-of-bounds in sg_copy_buffer+0x150/0x1c0 Read of size 4096 at addr ffff888109720800 by task kworker/1:0H/25 Workqueue: ib-comp-wq ib_cq_poll_work Call Trace: sg_copy_buffer+0x150/0x1c0 isert_recv_done+0xba6/0x2390 __ib_process_cq+0xe1/0x390 ib_cq_poll_work+0x46/0x150 isert_recv_done+0xba6 resolves to isert_handle_iscsi_dataout() (ib_isert.c:1160), inlined through isert_rx_opcode(). Validate wc->byte_len against the framing in isert_recv_done() before the PDU reaches any handler, and reinstate the connection if it is short. Because the test compares without subtracting the header length, it also rejects PDUs shorter than the iSER and iSCSI headers, which would otherwise be parsed out of stale descriptor contents. The login handler rejects PDUs shorter than ISER_HEADERS_LEN (commit 29e7b925ae6d ("IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN")) but does not bound the declared length either; that is fixed in the next patch. The data handlers had no length check at all. isert reads the data segment from a fixed offset: isert_get_data() returns the iSER header plus ISER_HEADERS_LEN and makes no adjustment for an AHS. The bytes the handlers touch are therefore exactly [ISER_HEADERS_LEN, ISER_HEADERS_LEN + dlength), and comparing that sum against wc->byte_len bounds precisely the region that is read. An AHS term would only make the test stricter without bounding anything furth ---truncated---
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux b8d26b3be8b33682cf163274ed07479a70554633 ~ b4706722ed3ea72882b3c986a19b4a1ba66384c4 -
Linux Linux 3.10 -

II. Public POCs for CVE-2026-90414

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III. Intelligence Information for CVE-2026-90414

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Patches & Fixes for CVE-2026-90414 (8)

Same Patch Batch · Linux · 2026-09-17 · 600 CVEs total

CVE-2026-92489 9.8 CRITICAL xfrm: Fix skb double-free in xfrm_dev_direct_output()
CVE-2026-90104 9.8 CRITICAL NFSv4.1: zero referring call lists before decoding
CVE-2026-90173 9.8 CRITICAL smb: smbdirect: free completion queues with ib_free_cq()
CVE-2026-90151 9.8 CRITICAL NFSv4: remove callback IDR entry on client allocation failure
CVE-2026-90235 9.8 CRITICAL sunrpc: xprtsock: annotate shared socket callbacks with READ_ONCE/WRITE_ONCE
CVE-2026-90110 9.4 CRITICAL inetpeer: randomize RB-tree node comparison using SipHash
CVE-2026-90230 9.1 CRITICAL nvmet: fix heap out-of-bounds read in nvmet_auth_negotiate()
CVE-2026-90413 9.1 CRITICAL IB/isert: reject login PDUs declaring more data than was received
CVE-2026-90381 8.8 HIGH wifi: mt76: fix handling channel context with different bands in mt76_switch_vif_chanctx()
CVE-2026-93189 8.8 HIGH HID: core: quiesce input in hid_hw_stop() to prevent use-after-free
CVE-2026-90329 8.8 HIGH HID: synchronize input before cleaning up a failed probe
CVE-2026-90256 8.8 HIGH Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind
CVE-2026-90357 8.8 HIGH wifi: mt76: mt7915: unlink TWT flow if the MCU rejects the agreement
CVE-2026-90255 8.8 HIGH Bluetooth: hci_conn: fix the SCO setup context lifetime
CVE-2026-90367 8.8 HIGH wifi: mt76: mt7996: hold dev->mt76.mutex while disabling tx worker in SER
CVE-2026-90286 8.8 HIGH drm/amdgpu/gfx6: Use PFP on the compute queues too
CVE-2026-90240 8.8 HIGH iommu/vt-d: Flush context cache with correct SID when tearing down aliases
CVE-2026-90380 8.8 HIGH wifi: mt76: mt792x: fix use-after-free in mt76_rx_poll_complete
CVE-2026-90379 8.8 HIGH wifi: mt76: mt7921: Add PCIe AER handler support to prevent system crash
CVE-2026-90162 8.8 HIGH ksmbd: defer publishing granted locks to prevent UAF/double-free race

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IV. Related Vulnerabilities

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Same vendor: Linux

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