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Unscored CVE-2026-31411 EUVD-2026-20469GHSA-9q92-j4jr-j3jp

net: atm: fix crash due to unvalidated vcc pointer in sigd_send()

Published Apr 8, 2026 · Updated Nov 10, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.4 Package: linux-aws-5.8 Package: linux-aws-6.14 Package: linux-aws-6.17 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-fips Package: linux-aws-hwe Package: linux-azure Package: linux-azure-4.15 Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.14 Package: linux-azure-6.17 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.15 Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-azure-nvidia-6.14 Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-4.15 Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.14 Package: linux-gcp-6.17 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.14 Package: linux-hwe-6.17 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-5.4 Package: linux-ibm-6.8 Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-iot Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-lts-xenial Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.17 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.11 Package: linux-oem-6.14 Package: linux-oem-6.17 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.4 Package: linux-oracle-5.8 Package: linux-oracle-6.14 Package: linux-oracle-6.17 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 Package: linux-realtime-6.17 Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.14 Package: linux-riscv-6.17 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

In the Linux kernel, the following vulnerability has been resolved:

net: atm: fix crash due to unvalidated vcc pointer in sigd_send()

Reproducer available at [1].

The ATM send path (sendmsg -> vcc_sendmsg -> sigd_send) reads the vcc
pointer from msg->vcc and uses it directly without any validation. This
pointer comes from userspace via sendmsg() and can be arbitrarily forged:

int fd = socket(AF_ATMSVC, SOCK_DGRAM, 0);
ioctl(fd, ATMSIGD_CTRL); // become ATM signaling daemon
struct msghdr msg = { .msg_iov = &iov, ... };
*(unsigned long *)(buf + 4) = 0xdeadbeef; // fake vcc pointer
sendmsg(fd, &msg, 0); // kernel dereferences 0xdeadbeef

In normal operation, the kernel sends the vcc pointer to the signaling
daemon via sigd_enq() when processing operations like connect(), bind(),
or listen(). The daemon is expected to return the same pointer when
responding. However, a malicious daemon can send arbitrary pointer values.

Fix this by introducing find_get_vcc() which validates the pointer by
searching through vcc_hash (similar to how sigd_close() iterates over
all VCCs), and acquires a reference via sock_hold() if found.

Since struct atm_vcc embeds struct sock as its first member, they share
the same lifetime. Therefore using sock_hold/sock_put is sufficient to
keep the vcc alive while it is being used.

Note that there may be a race with sigd_close() which could mark the vcc
with various flags (e.g., ATM_VF_RELEASED) after find_get_vcc() returns.
However, sock_hold() guarantees the memory remains valid, so this race
only affects the logical state, not memory safety.

[1]: https://gist.github.com/mrpre/1ba5949c45529c511152e2f4c755b0f3

Affected products

VendorProductAffectedFixed
Linux Linux 2.6.12 5.10.252

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 linux 6.18.14-1 —
Debian 13 linux 6.12.85-1 —
Debian 12 linux 6.1.170-1 —
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1026.30 —
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1096.98 —
Ubuntu 25.10 linux +8 No fix yet —
Ubuntu 24.04 LTS linux 6.8.0-134.134 USN-8492-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1060.63 USN-8492-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1063.71 USN-8606-1
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1062.69 USN-8607-1
Ubuntu 24.04 LTS linux-azure-nvidia 6.8.0-1039.42 —
Ubuntu 24.04 LTS linux-gcp 6.8.0-1063.69 USN-8492-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1058.64 USN-8492-2
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1045.48 USN-8492-2
Ubuntu 24.04 LTS linux-ibm 6.8.0-1060.61 USN-8492-1
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-134.134.1 USN-8497-1
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1058.61 USN-8492-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1058.61.1 USN-8492-2
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1029.30 USN-8498-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1057.58 USN-8492-1
Ubuntu 24.04 LTS linux-raspi 6.8.0-1060.64 USN-8492-4
Ubuntu 24.04 LTS linux-riscv +26 No fix yet —
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1032.33 USN-8499-1
Ubuntu 22.04 LTS linux 5.15.0-186.196 USN-8575-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1112.119 USN-8575-2
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1060.63~22.04.1 USN-8492-2
Ubuntu 22.04 LTS linux-azure +1 5.15.0-1117.126 USN-8610-1, USN-8575-3
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1063.71~22.04.1 USN-8606-1
Ubuntu 22.04 LTS linux-azure-fde-6.8 6.8.0-1062.69~22.04.1 USN-8609-1
Ubuntu 22.04 LTS linux-gcp 5.15.0-1112.122 USN-8575-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1063.69~22.04.1 USN-8492-2
Ubuntu 22.04 LTS linux-gke 5.15.0-1108.114 USN-8575-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1095.103 USN-8575-1
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-136.136~22.04.1 USN-8619-1
Ubuntu 22.04 LTS linux-ibm 5.15.0-1106.110 USN-8575-2
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1060.61~22.04.1 USN-8492-2
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1107.113 USN-8620-4
Ubuntu 22.04 LTS linux-kvm 5.15.0-1104.109 USN-8575-1
Ubuntu 22.04 LTS linux-lowlatency 5.15.0-184.194 USN-8575-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-134.134.1~22.04.1 USN-8497-1
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1107.108 USN-8575-2
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1058.61~22.04.1 USN-8492-1
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1064.66 USN-8576-2
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1053.53 USN-8576-2
Ubuntu 22.04 LTS linux-oracle 5.15.0-1109.115 USN-8575-3
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1057.58~22.04.1 USN-8492-2
Ubuntu 22.04 LTS linux-raspi 5.15.0-1106.109 USN-8668-2
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 22.04 LTS linux-riscv-6.8 6.8.0-134.134~22.04.1 —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1075.79 USN-8575-1
Show 18 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-raspi-realtime 6.8.0-2049.50 USN-8492-3
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1055.56 USN-8492-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 +1 No fix yet —
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1104.106 USN-8620-3
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1111.120 USN-8575-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1055.56~22.04.1 USN-8492-1
Ubuntu Pro FIPS 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 16.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-updates 24.04 LTS linux-aws-fips 6.8.0-1060.63+fips1 USN-8492-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-azure-fips 6.8.0-1062.69+fips1 USN-8492-5
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-134.134+fips1 USN-8492-5
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips 6.8.0-1063.69+fips1 USN-8492-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1112.119+fips1 USN-8575-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1117.126+fips1 USN-8620-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-186.196+fips1 USN-8575-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1112.122+fips1 USN-8575-1
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 16.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux +10 No fix yet —
Ubuntu Pro 20.04 LTS linux-aws-5.15 5.15.0-1112.119~20.04.1 USN-8575-2
Ubuntu Pro 20.04 LTS linux-azure-5.15 5.15.0-1117.126~20.04.1 USN-8620-1
Ubuntu Pro 20.04 LTS linux-azure-fde-5.15 5.15.0-1117.126~20.04.2 USN-8620-1
Ubuntu Pro 20.04 LTS linux-gcp-5.15 5.15.0-1112.122~20.04.1 USN-8668-1
Ubuntu Pro 20.04 LTS linux-hwe-5.15 5.15.0-186.196~20.04.1 USN-8575-1
Ubuntu Pro 20.04 LTS linux-ibm-5.15 +1 5.15.0-1106.110~20.04.1 USN-8597-1
Ubuntu Pro 20.04 LTS linux-intel-iotg-5.15 5.15.0-1107.113~20.04.1 USN-8620-3
Ubuntu Pro 20.04 LTS linux-lowlatency-hwe-5.15 5.15.0-184.194~20.04.1 USN-8575-1
Ubuntu Pro 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1064.66~20.04.1 USN-8576-1
Ubuntu Pro 20.04 LTS linux-oracle-5.15 5.15.0-1109.115~20.04.1 USN-8620-1
Ubuntu Pro 18.04 LTS linux +12 No fix yet —
Ubuntu Pro 16.04 LTS linux +7 No fix yet —
Ubuntu Pro 14.04 LTS linux +3 No fix yet —
ReleasePackageFixed inAdvisory
RHEL 9 rv +75 5.14.0-687.20.1.el9_8 RHSA-2026:33285
RHEL 8 kernel-rt +12 4.18.0-553.143.1.rt7.484.el8_10 RHSA-2026:39082
RHEL 8 perf +26 4.18.0-553.143.1.el8_10 RHSA-2026:39083
Show 10 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
RHEL 9.6 EUS rv +77 5.14.0-570.135.1.el9_6 RHSA-2026:56574
RHEL 9.4 E4S bpftool 7.3.0-427.145.1.el9_4 RHSA-2026:56573
RHEL 9.4 E4S rv +62 5.14.0-427.145.1.el9_4 RHSA-2026:56573
RHEL 9.2 E4S bpftool 7.0.0-284.188.1.el9_2 RHSA-2026:59662
RHEL 9.2 E4S kernel-rt +14 5.14.0-284.188.1.rt14.473.el9_2 RHSA-2026:59663
RHEL 9.2 E4S perf +47 5.14.0-284.188.1.el9_2 RHSA-2026:59662
RHEL 8.8 TUS perf +17 4.18.0-477.161.1.el8_8 RHSA-2026:61256
RHEL 8.8 E4S perf +18 4.18.0-477.161.1.el8_8 RHSA-2026:61256
RHEL 8.6 EUS Long Life perf +17 4.18.0-372.208.1.el8_6 RHSA-2026:59473
RHEL 8.6 AUS perf +17 4.18.0-372.208.1.el8_6 RHSA-2026:59473
RHEL 8.4 EUS Long Life perf +17 4.18.0-305.206.1.el8_4 RHSA-2026:65710
RHEL 8.4 AUS perf +17 4.18.0-305.206.1.el8_4 RHSA-2026:65710
RHEL 6 ELS perf +13 2.6.32-754.65.1.el6 RHSA-2026:83796

AlmaLinux

Errata ↗
ReleasePackageFixed inAdvisory
AlmaLinux 9 rv +73 5.14.0-687.20.1.el9_8 ALSA-2026:33285
AlmaLinux 8 kernel-rt +9 4.18.0-553.143.1.rt7.484.el8_10 ALSA-2026:39082
AlmaLinux 8 perf +24 4.18.0-553.143.1.el8_10 ALSA-2026:39083
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +7 6.4.0-150700.53.55.1 SUSE-SU-2026:2238-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.55.1.150700.17.33.1 SUSE-SU-2026:2238-1
Show 2 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLE Micro 6.2 kernel-syms +1 6.12.0-160000.33.1 SUSE-SU-2026:21834-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.55.1 SUSE-SU-2026:2238-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_15 1-150700.15.3.1 SUSE-SU-2026:2238-1

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-202.76.4.1.el10uek ELSA-2026-50372, ELSA-2026-50260
Oracle Linux 9 rv +28 5.14.0-687.20.1.el9_8 ELSA-2026-33285
Oracle Linux 8 kernel-uek +17 5.15.0-320.202.8.2.el9uek ELSA-2026-50261
Oracle Linux 8 perf +19 4.18.0-553.143.1.el8_10 ELSA-2026-50261, ELSA-2026-39083

Advisories 50

References