cbcvebase.
CVE-2026-31411
published 2026-04-08

CVE-2026-31411: 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…

PriorityP424medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.13%
3.1th percentile
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

71 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.18.14-1 (forky)linux 6.18.14-1 (forky)
linuxlinux
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c96549d07dfdd51aadf0722cfb40711574424840c96549d07dfdd51aadf0722cfb40711574424840
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1c8bda3df028d5e54134077dcd09f46ca8cfceb51c8bda3df028d5e54134077dcd09f46ca8cfceb5
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3e1a8b00095246a9a2b46b57f6d471c6d3c00ed23e1a8b00095246a9a2b46b57f6d471c6d3c00ed2
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e3f80666c2739296c3b69a127300455c43aa1067e3f80666c2739296c3b69a127300455c43aa1067
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 21c303fec138c002f90ed33bce60e807d53072bb21c303fec138c002f90ed33bce60e807d53072bb
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 69d3f9ee5489e6e8b66defcfa226e91d8239329769d3f9ee5489e6e8b66defcfa226e91d82393297
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 440c9a5fc477a8ee259d8bf669531250b8398651440c9a5fc477a8ee259d8bf669531250b8398651
linuxlinux>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ae88a5d2f29b69819dc7b04086734439d074a643ae88a5d2f29b69819dc7b04086734439d074a643
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.18.14-16.18.14-1
linuxlinux_kernel>= 2.6.12.1 < 5.10.2525.10.252
linuxlinux_kernel>= 5.11 < 5.15.2025.15.202
linuxlinux_kernel>= 5.16 < 6.1.1656.1.165

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vendor_ubuntu8.8HIGH
vendor_redhat7.0MEDIUM
Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.