Linux Kernel up to 7.0.12 IB ib_isert.c isert_login_recv_done negative out-of-bounds

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.0.12. It has been rated as critical. The affected element is the function isert_login_recv_done of the file drivers/infiniband/ulp/isert/ib_isert.c of the component IB. The manipulation of the argument negative leads to out-of-bounds. This vulnerability is traded as CVE-2026-53176. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 7.0.12. This issue affects the function isert_login_recv_done of the file drivers/infiniband/ulp/isert/ib_isert.c of the component IB. The manipulation of the argument negative with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality. The summary by CVE is:

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 advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-53176 since 06/09/2026. The attack may be initiated remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/25/2026).

Upgrading to version 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36 or 7.0.13 eliminates this vulnerability. Applying the patch 75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefb/e8a013c0c3ca2f6708341a56612a3f6d6921620a/bd22740d7f14cb1c0289444cfd2c8d2938667c1d/c1234229399f4af12c553b1b0ffd978eeba65548/c5584e089b5af7b3bf8bd5e8ca0560cbf32b0a47/df422fd273c96c2ee5beb80fc21adc8c70c29260/1ca40b243277c9e88be5e00bd3e083f71aefb93e/29e7b925ae6df64894e82ab6419994dc25580a8a is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.258
• 5.15.209
• 6.1.175
• 6.6.142
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
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• 6.12.12
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• 6.12.86
• 6.12.87
• 6.12.88
• 6.12.89
• 6.12.90
• 6.12.91
• 6.12.92
• 6.12.93
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
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• 6.18.29
• 6.18.30
• 6.18.31
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• 6.18.33
• 6.18.34
• 6.18.35
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.0.7
• 7.0.8
• 7.0.9
• 7.0.10
• 7.0.11
• 7.0.12

License

• open-source

Website

• Vendor: https://www.kernel.org/

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