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Fencer Vulns
medium 5.5

CVE-2024-40966 json

tty: add the option to have a tty reject a new ldisc

published 2024-07-12 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-38763

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

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

tty: add the option to have a tty reject a new ldisc

... and use it to limit the virtual terminals to just N_TTY. They are kind of special, and in particular, the "con_write()" routine violates the "writes cannot sleep" rule that some ldiscs rely on.

This avoids the

BUG: sleeping function called from invalid context at kernel/printk/printk.c:2659

when N_GSM has been attached to a virtual console, and gsmld_write() calls con_write() while holding a spinlock, and con_write() then tries to get the console lock.

Patch / fix

  • Linux Linux 6.1.96, 6.6.36, 6.9.7, 6.10
  • linux Debian 12 6.1.99-1
  • linux Debian 14, Debian 13 6.9.7-1

debian advisories DEBIAN-CVE-2024-40966

  • linux Ubuntu 24.04 LTS 6.8.0-44.44
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1015.16
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1014.16
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1010.13
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1012.12
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1014.16
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1011.12
  • linux-riscv Ubuntu 24.04 LTS 6.8.0-44.44.1

ubuntu advisories UBUNTU-CVE-2024-40966

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 RHEL 9 5.14.0-503.11.1.el9_5
  • rv RHEL 9 5.14.0-503.11.1.el9_5
  • perf RHEL 9 5.14.0-503.11.1.el9_5
  • rtla RHEL 9 5.14.0-503.11.1.el9_5
  • bpftool RHEL 9 7.4.0-503.11.1.el9_5
  • libperf RHEL 9 5.14.0-503.11.1.el9_5
  • kernel-rt RHEL 9 5.14.0-503.11.1.el9_5
  • kernel-64k RHEL 9 5.14.0-503.11.1.el9_5

red hat advisories RHSA-2024:9315

  • kernel-rt Linux Micro 6.0 6.4.0-9.1
  • kernel-source-rt Linux Micro 6.0 6.4.0-9.1
  • kernel-source Linux Micro 6.0 6.4.0-18.1
  • kernel-default Linux Micro 6.0 6.4.0-18.1
  • kernel-kvmsmall Linux Micro 6.0 6.4.0-18.1
  • kernel-default-base Linux Micro 6.0 6.4.0-17.1.1.51
  • kernel-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.5.1
  • kernel-syms-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.5.1

suse advisories SUSE-SU-2025:20028-1SUSE-SU-2025:20008-1SUSE-SU-2024:2973-1SUSE-SU-2024:2947-1SUSE-SU-2024:2940-1SUSE-SU-2024:2939-1

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-2024-40966 updated cvss 4.4

kernel: tty: add the option to have a tty reject a new ldisc

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 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 planned “Will not fix”
  • Red Hat CodeReady Linux Builder (v. 9) libperf 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-s390x 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-x86_64 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-aarch64 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-ppc64le 5.14.0-503.11.1.el9_5 Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-503.11.1.el9_5, perf 5.14.0-503.11.1.el9_5, rtla 5.14.0-503.11.1.el9_5, kernel-devel-matched 5.14.0-503.11.1.el9_5, kernel-64k-devel-matched 5.14.0-503.11.1.el9_5, kernel-debug-devel-matched 5.14.0-503.11.1.el9_5, +6 more Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.4.0-503.11.1.el9_5, kernel 5.14.0-503.11.1.el9_5, kernel-64k 5.14.0-503.11.1.el9_5, kernel-core 5.14.0-503.11.1.el9_5, kernel-tools 5.14.0-503.11.1.el9_5, python3-perf 5.14.0-503.11.1.el9_5, +29 more Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-503.11.1.el9_5, kernel-rt-core 5.14.0-503.11.1.el9_5, kernel-rt-modules 5.14.0-503.11.1.el9_5, kernel-rt-debug-core 5.14.0-503.11.1.el9_5, kernel-rt-modules-core 5.14.0-503.11.1.el9_5, kernel-rt-debug-modules 5.14.0-503.11.1.el9_5, +4 more Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-503.11.1.el9_5, kernel-rt-kvm 5.14.0-503.11.1.el9_5, kernel-rt-core 5.14.0-503.11.1.el9_5, kernel-rt-modules 5.14.0-503.11.1.el9_5, kernel-rt-debug-kvm 5.14.0-503.11.1.el9_5, kernel-rt-debug-core 5.14.0-503.11.1.el9_5, +6 more
    fixed: vendor fix RHSA-2024:9315
  • Red Hat CodeReady Linux Builder (v. 9) kernel-cross-headers 5.14.0-503.11.1.el9_5 Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux AppStream (v. 9) kernel-headers 5.14.0-503.11.1.el9_5
    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
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

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.