Linux Kernel up to 7.1-rc2 Initial Soft RoCE Driver payload_size out-of-bounds

Summaryinfo

A vulnerability categorized as critical has been discovered in Linux Kernel up to 6.6.139/6.12.87/6.18.29/7.0.6/7.1-rc2. The impacted element is the function payload_size of the component Initial Soft RoCE Driver. Such manipulation leads to out-of-bounds. This vulnerability is documented as CVE-2026-46133. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Linux Kernel up to 6.6.139/6.12.87/6.18.29/7.0.6/7.1-rc2. Affected by this issue is the function payload_size of the component Initial Soft RoCE Driver. The manipulation 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. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Reject unknown opcodes before ICRC processing Even after applying commit 7244491dab34 ("RDMA/rxe: Validate pad and ICRC before payload_size() in rxe_rcv"), a single unauthenticated UDP packet can still trigger panic. That patch handled payload_size() underflow only for valid opcodes with short packets, not for packets carrying an unknown opcode. The unknown-opcode OOB read described below predates that commit and reaches back to the initial Soft RoCE driver. The check added there reads pkt->paylen < header_size(pkt) + bth_pad(pkt) + RXE_ICRC_SIZE where header_size(pkt) expands to rxe_opcode[pkt->opcode].length. The rxe_opcode[] array has 256 entries but is only populated for defined IB opcodes; any other entry (for example opcode 0xff) is zero-initialized, so length == 0 and the check degenerates to pkt->paylen < 0 + bth_pad(pkt) + RXE_ICRC_SIZE which does not constrain pkt->paylen enough. rxe_icrc_hdr() then computes rxe_opcode[pkt->opcode].length - RXE_BTH_BYTES which underflows when length == 0 and passes a huge value to rxe_crc32(), causing an out-of-bounds read of the skb payload. Reproduced on v7.0-rc7 with that fix applied, QEMU/KVM with CONFIG_RDMA_RXE=y and CONFIG_KASAN=y, after rdma link add rxe0 type rxe netdev eth0 A single 48-byte UDP packet to port 4791 with BTH opcode=0xff and QPN=IB_MULTICAST_QPN triggers: BUG: KASAN: slab-out-of-bounds in crc32_le+0x115/0x170 Read of size 1 at addr ... The buggy address is located 0 bytes to the right of allocated 704-byte region Call Trace: crc32_le+0x115/0x170 rxe_icrc_hdr.isra.0+0x226/0x300 rxe_icrc_check+0x13f/0x3a0 rxe_rcv+0x6e1/0x16e0 rxe_udp_encap_recv+0x20a/0x320 udp_queue_rcv_one_skb+0x7ed/0x12c0 Subsequent packets with the same shape fault on unmapped memory and panic the kernel. The trigger requires only module load and "rdma link add"; no QP, no connection, and no authentication. Fix this by rejecting packets whose opcode has no rxe_opcode[] entry, detected via the zero mask or zero length, before any length arithmetic runs.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2026-46133 since 05/13/2026. The exploitation is known to be difficult. Technical details are known, but there is no available exploit.

Upgrading to version 6.6.140, 6.12.88, 6.18.30, 7.0.7 or 7.1-rc3 eliminates this vulnerability. Applying the patch e3dc3a2fb05f4ed49c7f20594c4c52350d032189/f8ee926431a7bbec2b10c1290664af2cb290b983/006a3a5f75345c6a0dbf13fd3ee01406e93b6733/6fa18025e5782afff91415fd5217b39c1e4837d7/4c6f86d85d03cdb33addce86aa69aa795ca6c47a 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

• 6.6.139
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
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• 6.12.13
• 6.12.14
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• 6.12.16
• 6.12.17
• 6.12.18
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• 6.12.20
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• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
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• 6.12.53
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• 6.12.55
• 6.12.56
• 6.12.57
• 6.12.58
• 6.12.59
• 6.12.60
• 6.12.61
• 6.12.62
• 6.12.63
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• 6.12.65
• 6.12.66
• 6.12.67
• 6.12.68
• 6.12.69
• 6.12.70
• 6.12.71
• 6.12.72
• 6.12.73
• 6.12.74
• 6.12.75
• 6.12.76
• 6.12.77
• 6.12.78
• 6.12.79
• 6.12.80
• 6.12.81
• 6.12.82
• 6.12.83
• 6.12.84
• 6.12.85
• 6.12.86
• 6.12.87
• 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
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.1-rc1
• 7.1-rc2

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Sourcesinfo

Entryinfo

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