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Fencer Vulns
high 7.5

CVE-2026-46133 json

RDMA/rxe: Reject unknown opcodes before ICRC processing

published 2026-05-28 5 mo ago modified 2026-10-19 20 d ago also EUVD-2026-32760

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7, 7.1
  • linux Debian 12 6.1.176-1
  • linux Debian 13 6.12.88-1
  • linux Debian 14 7.0.7-1

debian advisories DEBIAN-CVE-2026-46133

  • linux Ubuntu 22.04 LTS 5.15.0-186.196
  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux Ubuntu 26.04 LTS 7.0.0-28.28
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1112.119
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1009.9
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1112.122
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72

ubuntu advisories UBUNTU-CVE-2026-46133

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-kvm RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-core RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-modules RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-debug-kvm RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-debug-core RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-debug-modules RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-modules-extra RHEL 8 4.18.0-553.166.1.rt7.507.el8_10

red hat advisories RHSA-2026:77219RHSA-2026:77301RHSA-2026:77218RHSA-2026:77217RHSA-2026:77216RHSA-2026:70403

  • kernel-rt Linux Micro 6.2 6.12.0-160000.38.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.38.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1.160000.2.23
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-azure SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.38.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.38.1

suse advisories SUSE-SU-2026:23887-1SUSE-SU-2026:23902-1SUSE-SU-2026:23897-1SUSE-SU-2026:23881-1SUSE-SU-2026:2914-1SUSE-SU-2026:2800-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1openSUSE-SU-2026:10954-1

  • kernel AlmaLinux 8 4.18.0-553.166.1.el8_10
  • perf AlmaLinux 8 4.18.0-553.166.1.el8_10
  • bpftool AlmaLinux 8 4.18.0-553.166.1.el8_10
  • kernel-core AlmaLinux 8 4.18.0-553.166.1.el8_10
  • kernel-tools AlmaLinux 8 4.18.0-553.166.1.el8_10
  • python3-perf AlmaLinux 8 4.18.0-553.166.1.el8_10
  • kernel-modules AlmaLinux 8 4.18.0-553.166.1.el8_10
  • kernel-zfcpdump AlmaLinux 8 4.18.0-553.166.1.el8_10

almalinux advisories ALSA-2026:70402ALSA-2026:70403ALSA-2026:68570

  • kernel-rt Rocky Linux 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel Rocky Linux 8 4.18.0-553.166.1.el8_10
  • kernel Rocky Linux 9 5.14.0-687.49.1.el9_8

rocky linux advisories RLSA-2026:70403RLSA-2026:70402RLSA-2026:68570

  • kernel Azure Linux 3.0 6.6.141.1-1

azure linux advisories AZL-89102

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-46133 updated cvss 7.5

kernel: RDMA/rxe: Reject unknown opcodes before ICRC processing

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.6) libperf 5.14.0-570.147.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.147.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.147.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.147.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.147.1.el9_6
    fixed: vendor fix RHSA-2026:77219
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.49.1.el9_8, perf 5.14.0-687.49.1.el9_8, rtla 5.14.0-687.49.1.el9_8, python3-perf 5.14.0-687.49.1.el9_8, kernel-devel-matched 5.14.0-687.49.1.el9_8, kernel-64k-devel-matched 5.14.0-687.49.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:68570
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) rv 5.14.0-427.154.1.el9_4, perf 5.14.0-427.154.1.el9_4, rtla 5.14.0-427.154.1.el9_4, kernel-devel-matched 5.14.0-427.154.1.el9_4, kernel-64k-devel-matched 5.14.0-427.154.1.el9_4, kernel-debug-devel-matched 5.14.0-427.154.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:77218
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) rv 5.14.0-570.147.1.el9_6, perf 5.14.0-570.147.1.el9_6, rtla 5.14.0-570.147.1.el9_6, python3-perf 5.14.0-570.147.1.el9_6, kernel-devel-matched 5.14.0-570.147.1.el9_6, kernel-64k-devel-matched 5.14.0-570.147.1.el9_6, +7 more
    fixed: vendor fix RHSA-2026:77219
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.166.1.el8_10, kernel 4.18.0-553.166.1.el8_10, bpftool 4.18.0-553.166.1.el8_10, kernel-core 4.18.0-553.166.1.el8_10, kernel-tools 4.18.0-553.166.1.el8_10, python3-perf 4.18.0-553.166.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:70402
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.49.1.el9_8, kernel-64k 5.14.0-687.49.1.el9_8, kernel-core 5.14.0-687.49.1.el9_8, kernel-tools 5.14.0-687.49.1.el9_8, kernel-modules 5.14.0-687.49.1.el9_8, kernel-64k-core 5.14.0-687.49.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:68570
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) perf 4.18.0-305.211.1.el8_4, kernel 4.18.0-305.211.1.el8_4, bpftool 4.18.0-305.211.1.el8_4, kernel-core 4.18.0-305.211.1.el8_4, kernel-tools 4.18.0-305.211.1.el8_4, python3-perf 4.18.0-305.211.1.el8_4, +8 more
    fixed: vendor fix RHSA-2026:77217
show 18 more
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) perf 4.18.0-372.220.1.el8_6, kernel 4.18.0-372.220.1.el8_6, bpftool 4.18.0-372.220.1.el8_6, kernel-core 4.18.0-372.220.1.el8_6, kernel-tools 4.18.0-372.220.1.el8_6, python3-perf 4.18.0-372.220.1.el8_6, +8 more
    fixed: vendor fix RHSA-2026:77216
  • Red Hat Enterprise Linux BaseOS E4S (v.8.8) perf 4.18.0-477.172.1.el8_8, kernel 4.18.0-477.172.1.el8_8, bpftool 4.18.0-477.172.1.el8_8, kernel-core 4.18.0-477.172.1.el8_8, kernel-tools 4.18.0-477.172.1.el8_8, python3-perf 4.18.0-477.172.1.el8_8, +9 more
    fixed: vendor fix RHSA-2026:77301
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool 7.3.0-427.154.1.el9_4, kernel 5.14.0-427.154.1.el9_4, kernel-64k 5.14.0-427.154.1.el9_4, kernel-core 5.14.0-427.154.1.el9_4, kernel-tools 5.14.0-427.154.1.el9_4, python3-perf 5.14.0-427.154.1.el9_4, +28 more
    fixed: vendor fix RHSA-2026:77218
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel 5.14.0-570.147.1.el9_6, kernel-64k 5.14.0-570.147.1.el9_6, kernel-core 5.14.0-570.147.1.el9_6, kernel-tools 5.14.0-570.147.1.el9_6, kernel-modules 5.14.0-570.147.1.el9_6, kernel-64k-core 5.14.0-570.147.1.el9_6, +27 more
    fixed: vendor fix RHSA-2026:77219
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) perf 4.18.0-305.211.1.el8_4, kernel 4.18.0-305.211.1.el8_4, bpftool 4.18.0-305.211.1.el8_4, kernel-core 4.18.0-305.211.1.el8_4, kernel-tools 4.18.0-305.211.1.el8_4, python3-perf 4.18.0-305.211.1.el8_4, +15 more
    fixed: vendor fix RHSA-2026:77217
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) perf 4.18.0-372.220.1.el8_6, kernel 4.18.0-372.220.1.el8_6, bpftool 4.18.0-372.220.1.el8_6, kernel-core 4.18.0-372.220.1.el8_6, kernel-tools 4.18.0-372.220.1.el8_6, python3-perf 4.18.0-372.220.1.el8_6, +15 more
    fixed: vendor fix RHSA-2026:77216
  • Red Hat Enterprise Linux BaseOS TUS (v.8.8) perf 4.18.0-477.172.1.el8_8, kernel 4.18.0-477.172.1.el8_8, bpftool 4.18.0-477.172.1.el8_8, kernel-core 4.18.0-477.172.1.el8_8, kernel-tools 4.18.0-477.172.1.el8_8, python3-perf 4.18.0-477.172.1.el8_8, +8 more
    fixed: vendor fix RHSA-2026:77301
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.49.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.49.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.49.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.49.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.49.1.el9_8
    fixed: vendor fix RHSA-2026:68570
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.166.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.166.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.166.1.el8_10
    fixed: vendor fix RHSA-2026:70402
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-kvm 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-kvm 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-core 4.18.0-553.166.1.rt7.507.el8_10, +4 more
    fixed: vendor fix RHSA-2026:70403
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.49.1.el9_8, kernel-rt-64k 5.14.0-687.49.1.el9_8, kernel-rt-core 5.14.0-687.49.1.el9_8, kernel-rt-modules 5.14.0-687.49.1.el9_8, kernel-rt-64k-core 5.14.0-687.49.1.el9_8, kernel-rt-debug-core 5.14.0-687.49.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:68570
  • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt 5.14.0-427.154.1.el9_4, kernel-rt-core 5.14.0-427.154.1.el9_4, kernel-rt-modules 5.14.0-427.154.1.el9_4, kernel-rt-debug-core 5.14.0-427.154.1.el9_4, kernel-rt-modules-core 5.14.0-427.154.1.el9_4, kernel-rt-debug-modules 5.14.0-427.154.1.el9_4, +4 more
    fixed: vendor fix RHSA-2026:77218
  • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt 5.14.0-570.147.1.el9_6, kernel-rt-64k 5.14.0-570.147.1.el9_6, kernel-rt-core 5.14.0-570.147.1.el9_6, kernel-rt-modules 5.14.0-570.147.1.el9_6, kernel-rt-64k-core 5.14.0-570.147.1.el9_6, kernel-rt-debug-core 5.14.0-570.147.1.el9_6, +14 more
    fixed: vendor fix RHSA-2026:77219
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.49.1.el9_8, kernel-rt-core 5.14.0-687.49.1.el9_8, kernel-rt-modules 5.14.0-687.49.1.el9_8, kernel-rt-debug-core 5.14.0-687.49.1.el9_8, kernel-rt-modules-core 5.14.0-687.49.1.el9_8, kernel-rt-debug-modules 5.14.0-687.49.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:68570
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt 5.14.0-427.154.1.el9_4, kernel-rt-kvm 5.14.0-427.154.1.el9_4, kernel-rt-core 5.14.0-427.154.1.el9_4, kernel-rt-modules 5.14.0-427.154.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.154.1.el9_4, kernel-rt-debug-core 5.14.0-427.154.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:77218
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt 5.14.0-570.147.1.el9_6, kernel-rt-kvm 5.14.0-570.147.1.el9_6, kernel-rt-core 5.14.0-570.147.1.el9_6, kernel-rt-modules 5.14.0-570.147.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.147.1.el9_6, kernel-rt-debug-core 5.14.0-570.147.1.el9_6, +6 more
    fixed: vendor fix RHSA-2026:77219
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules-extra 4.18.0-553.166.1.rt7.507.el8_10, +2 more
    fixed: vendor fix RHSA-2026:70403
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
23 d ago

Exploit prediction

0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.