Skip to content
Fencer Vulns
high 7.8

CVE-2022-49977 json

ftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead

published 2025-06-18 16 mo ago modified 2026-08-05 3 mo ago also EUVD-2022-55257

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

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

ftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead

ftrace_startup does not remove ops from ftrace_ops_list when ftrace_startup_enable fails:

register_ftrace_function ftrace_startup __register_ftrace_function ... add_ftrace_ops(&ftrace_ops_list, ops) ... ... ftrace_startup_enable // if ftrace failed to modify, ftrace_disabled is set to 1 ... return 0 // ops is in the ftrace_ops_list.

When ftrace_disabled = 1, unregister_ftrace_function simply returns without doing anything: unregister_ftrace_function ftrace_shutdown if (unlikely(ftrace_disabled)) return -ENODEV; // return here, __unregister_ftrace_function is not executed, // as a result, ops is still in the ftrace_ops_list __unregister_ftrace_function ...

If ops is dynamically allocated, it will be free later, in this case, is_ftrace_trampoline accesses NULL pointer:

is_ftrace_trampoline ftrace_ops_trampoline do_for_each_ftrace_op(op, ftrace_ops_list) // OOPS! op may be NULL!

Syzkaller reports as follows: [ 1203.506103] BUG: kernel NULL pointer dereference, address: 000000000000010b [ 1203.508039] #PF: supervisor read access in kernel mode [ 1203.508798] #PF: error_code(0x0000) - not-present page [ 1203.509558] PGD 800000011660b067 P4D 800000011660b067 PUD 130fb8067 PMD 0 [ 1203.510560] Oops: 0000 [#1] SMP KASAN PTI [ 1203.511189] CPU: 6 PID: 29532 Comm: syz-executor.2 Tainted: G B W 5.10.0 #8 [ 1203.512324] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 1203.513895] RIP: 0010:is_ftrace_trampoline+0x26/0xb0 [ 1203.514644] Code: ff eb d3 90 41 55 41 54 49 89 fc 55 53 e8 f2 00 fd ff 48 8b 1d 3b 35 5d 03 e8 e6 00 fd ff 48 8d bb 90 00 00 00 e8 2a 81 26 00 <48> 8b ab 90 00 00 00 48 85 ed 74 1d e8 c9 00 fd ff 48 8d bb 98 00 [ 1203.518838] RSP: 0018:ffffc900012cf960 EFLAGS: 00010246 [ 1203.520092] RAX: 0000000000000000 RBX: 000000000000007b RCX: ffffffff8a331866 [ 1203.521469] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000000000010b [ 1203.522583] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8df18b07 [ 1203.523550] R10: fffffbfff1be3160 R11: 0000000000000001 R12: 0000000000478399 [ 1203.524596] R13: 0000000000000000 R14: ffff888145088000 R15: 0000000000000008 [ 1203.525634] FS: 00007f429f5f4700(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000 [ 1203.526801] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1203.527626] CR2: 000000000000010b CR3: 0000000170e1e001 CR4: 00000000003706e0 [ 1203.528611] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1203.529605] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Therefore, when ftrace_startup_enable fails, we need to rollback registration process and remove ops from ftrace_ops_list.

Patch / fix

  • Linux Linux 3.3, 3.5, 3.11, 3.13, 4.9.327, 4.14.292, 4.19.257, 5.4.212, 5.10.141, 5.15.65, 5.19.7, 6.0
  • linux Debian 14, Debian 13, Debian 12 6.0.2-1

debian advisories DEBIAN-CVE-2022-49977

  • linux Ubuntu 18.04 LTS 4.15.0-201.212
  • linux Ubuntu 20.04 LTS 5.4.0-132.148
  • linux Ubuntu 22.04 LTS 5.15.0-57.63
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1147.159
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1089.97
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1027.31
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1093.102
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1026.33

ubuntu advisories UBUNTU-CVE-2022-49977

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 4.18.0-553.64.1.rt7.405.el8_10
  • kernel-rt-kvm RHEL 8 4.18.0-553.64.1.rt7.405.el8_10
  • kernel-rt-core RHEL 8 4.18.0-553.64.1.rt7.405.el8_10
  • kernel-rt-modules RHEL 8 4.18.0-553.64.1.rt7.405.el8_10
  • kernel-rt-debug-kvm RHEL 8 4.18.0-553.64.1.rt7.405.el8_10
  • kernel-rt-debug-core RHEL 8 4.18.0-553.64.1.rt7.405.el8_10
  • kernel-rt-debug-modules RHEL 8 4.18.0-553.64.1.rt7.405.el8_10
  • kernel-rt-modules-extra RHEL 8 4.18.0-553.64.1.rt7.405.el8_10

red hat advisories RHSA-2025:15035RHSA-2025:14749RHSA-2025:14744RHSA-2025:14696RHSA-2025:14742RHSA-2025:14692

  • kernel-64kb SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS, SLE High Performance Computing 15 SP4-ESPOS 5.14.21-150400.24.170.2
  • kernel-syms SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +3 more 5.14.21-150400.24.170.1
  • kernel-source SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +3 more 5.14.21-150400.24.170.1
  • kernel-default SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +6 more 5.14.21-150400.24.170.2
  • kernel-zfcpdump SLES 15 SP4-LTSS, Manager Server 4.3 5.14.21-150400.24.170.2
  • kernel-obs-build SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 5.14.21-150400.24.170.2
  • kernel-default-base SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +5 more 5.14.21-150400.24.170.2.150400.24.86.2
  • kernel-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.124.1

suse advisories SUSE-SU-2025:02537-1SUSE-SU-2025:02334-1SUSE-SU-2025:02322-1SUSE-SU-2025:02321-1SUSE-SU-2025:02320-1SUSE-SU-2025:02308-1

  • kernel AlmaLinux 8 4.18.0-553.64.1.el8_10
  • perf AlmaLinux 8 4.18.0-553.64.1.el8_10
  • bpftool AlmaLinux 8 4.18.0-553.64.1.el8_10
  • kernel-core AlmaLinux 8 4.18.0-553.64.1.el8_10
  • kernel-tools AlmaLinux 8 4.18.0-553.64.1.el8_10
  • python3-perf AlmaLinux 8 4.18.0-553.64.1.el8_10
  • kernel-modules AlmaLinux 8 4.18.0-553.64.1.el8_10
  • kernel-zfcpdump AlmaLinux 8 4.18.0-553.64.1.el8_10

almalinux advisories ALSA-2025:11850ALSA-2025:11851

  • kernel-rt Rocky Linux 8 4.18.0-553.64.1.rt7.405.el8_10
  • kernel Rocky Linux 8 4.18.0-553.64.1.el8_10

rocky linux advisories RLSA-2025:11851RLSA-2025:11850

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-2022-49977 updated cvss 7.0

kernel: ftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • 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: no fix available
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-427.13.1.el9_4, perf 5.14.0-427.13.1.el9_4, rtla 5.14.0-427.13.1.el9_4, kernel-devel-matched 5.14.0-427.13.1.el9_4, kernel-64k-devel-matched 5.14.0-427.13.1.el9_4, kernel-debug-devel-matched 5.14.0-427.13.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:2394
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) perf 5.14.0-70.144.1.el9_0, kernel-devel-matched 5.14.0-70.144.1.el9_0, kernel-debug-devel-matched 5.14.0-70.144.1.el9_0, kernel-debuginfo-common-s390x 5.14.0-70.144.1.el9_0, kernel-zfcpdump-devel-matched 5.14.0-70.144.1.el9_0, kernel-debuginfo-common-x86_64 5.14.0-70.144.1.el9_0, +2 more
    fixed: vendor fix RHSA-2025:14744
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) perf 5.14.0-284.134.1.el9_2, rtla 5.14.0-284.134.1.el9_2, kernel-devel-matched 5.14.0-284.134.1.el9_2, kernel-64k-devel-matched 5.14.0-284.134.1.el9_2, kernel-debug-devel-matched 5.14.0-284.134.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.134.1.el9_2, +5 more
    fixed: vendor fix RHSA-2025:14696
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.64.1.el8_10, kernel 4.18.0-553.64.1.el8_10, bpftool 4.18.0-553.64.1.el8_10, kernel-core 4.18.0-553.64.1.el8_10, kernel-tools 4.18.0-553.64.1.el8_10, python3-perf 4.18.0-553.64.1.el8_10, +15 more
    fixed: vendor fix RHSA-2025:11850
  • Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.3.0-427.13.1.el9_4, kernel 5.14.0-427.13.1.el9_4, kernel-64k 5.14.0-427.13.1.el9_4, kernel-core 5.14.0-427.13.1.el9_4, kernel-tools 5.14.0-427.13.1.el9_4, python3-perf 5.14.0-427.13.1.el9_4, +28 more
    fixed: vendor fix RHSA-2024:2394
  • Red Hat Enterprise Linux BaseOS AUS (v. 8.2) perf 4.18.0-193.165.1.el8_2, kernel 4.18.0-193.165.1.el8_2, bpftool 4.18.0-193.165.1.el8_2, kernel-core 4.18.0-193.165.1.el8_2, kernel-tools 4.18.0-193.165.1.el8_2, python3-perf 4.18.0-193.165.1.el8_2, +8 more
    fixed: vendor fix RHSA-2025:14742
show 17 more
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) perf 4.18.0-305.170.1.el8_4, kernel 4.18.0-305.170.1.el8_4, bpftool 4.18.0-305.170.1.el8_4, kernel-core 4.18.0-305.170.1.el8_4, kernel-tools 4.18.0-305.170.1.el8_4, python3-perf 4.18.0-305.170.1.el8_4, +8 more
    fixed: vendor fix RHSA-2025:15035
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) perf 4.18.0-372.158.1.el8_6, kernel 4.18.0-372.158.1.el8_6, bpftool 4.18.0-372.158.1.el8_6, kernel-core 4.18.0-372.158.1.el8_6, kernel-tools 4.18.0-372.158.1.el8_6, python3-perf 4.18.0-372.158.1.el8_6, +8 more Red Hat Enterprise Linux BaseOS E4S (v.8.6) perf 4.18.0-372.158.1.el8_6, kernel 4.18.0-372.158.1.el8_6, bpftool 4.18.0-372.158.1.el8_6, kernel-core 4.18.0-372.158.1.el8_6, kernel-tools 4.18.0-372.158.1.el8_6, python3-perf 4.18.0-372.158.1.el8_6, +15 more
    fixed: vendor fix RHSA-2025:14692
  • Red Hat Enterprise Linux BaseOS E4S (v.8.8) perf 4.18.0-477.107.1.el8_8, kernel 4.18.0-477.107.1.el8_8, bpftool 4.18.0-477.107.1.el8_8, kernel-core 4.18.0-477.107.1.el8_8, kernel-tools 4.18.0-477.107.1.el8_8, python3-perf 4.18.0-477.107.1.el8_8, +9 more
    fixed: vendor fix RHSA-2025:14511
  • Red Hat Enterprise Linux BaseOS E4S (v.9.0) kernel 5.14.0-70.144.1.el9_0, bpftool 5.14.0-70.144.1.el9_0, kernel-core 5.14.0-70.144.1.el9_0, kernel-tools 5.14.0-70.144.1.el9_0, python3-perf 5.14.0-70.144.1.el9_0, kernel-modules 5.14.0-70.144.1.el9_0, +14 more
    fixed: vendor fix RHSA-2025:14744
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool 7.0.0-284.134.1.el9_2, kernel 5.14.0-284.134.1.el9_2, kernel-64k 5.14.0-284.134.1.el9_2, kernel-core 5.14.0-284.134.1.el9_2, kernel-tools 5.14.0-284.134.1.el9_2, python3-perf 5.14.0-284.134.1.el9_2, +28 more
    fixed: vendor fix RHSA-2025:14696
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) perf 4.18.0-305.170.1.el8_4, kernel 4.18.0-305.170.1.el8_4, bpftool 4.18.0-305.170.1.el8_4, kernel-core 4.18.0-305.170.1.el8_4, kernel-tools 4.18.0-305.170.1.el8_4, python3-perf 4.18.0-305.170.1.el8_4, +8 more
    fixed: vendor fix RHSA-2025:15035
  • Red Hat Enterprise Linux BaseOS TUS (v.8.6) perf 4.18.0-372.158.1.el8_6, kernel 4.18.0-372.158.1.el8_6, bpftool 4.18.0-372.158.1.el8_6, kernel-core 4.18.0-372.158.1.el8_6, kernel-tools 4.18.0-372.158.1.el8_6, python3-perf 4.18.0-372.158.1.el8_6, +8 more
    fixed: vendor fix RHSA-2025:14692
  • Red Hat Enterprise Linux BaseOS TUS (v.8.8) perf 4.18.0-477.107.1.el8_8, kernel 4.18.0-477.107.1.el8_8, bpftool 4.18.0-477.107.1.el8_8, kernel-core 4.18.0-477.107.1.el8_8, kernel-tools 4.18.0-477.107.1.el8_8, python3-perf 4.18.0-477.107.1.el8_8, +8 more
    fixed: vendor fix RHSA-2025:14511
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.64.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.64.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.64.1.el8_10
    fixed: vendor fix RHSA-2025:11850
  • Red Hat Enterprise Linux CRB (v. 9) libperf 5.14.0-427.13.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.13.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.13.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.13.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.13.1.el9_4
    fixed: vendor fix RHSA-2024:2394
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.64.1.rt7.405.el8_10, kernel-rt-kvm 4.18.0-553.64.1.rt7.405.el8_10, kernel-rt-core 4.18.0-553.64.1.rt7.405.el8_10, kernel-rt-modules 4.18.0-553.64.1.rt7.405.el8_10, kernel-rt-debug-kvm 4.18.0-553.64.1.rt7.405.el8_10, kernel-rt-debug-core 4.18.0-553.64.1.rt7.405.el8_10, +4 more
    fixed: vendor fix RHSA-2025:11851
  • Red Hat Enterprise Linux NFV (v. 9) kernel-rt 5.14.0-427.13.1.el9_4, kernel-rt-kvm 5.14.0-427.13.1.el9_4, kernel-rt-core 5.14.0-427.13.1.el9_4, kernel-rt-modules 5.14.0-427.13.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.13.1.el9_4, kernel-rt-debug-core 5.14.0-427.13.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:2394
  • Red Hat Enterprise Linux NFV E4S (v.9.0) kernel-rt 5.14.0-70.144.1.rt21.216.el9_0, kernel-rt-kvm 5.14.0-70.144.1.rt21.216.el9_0, kernel-rt-core 5.14.0-70.144.1.rt21.216.el9_0, kernel-rt-modules 5.14.0-70.144.1.rt21.216.el9_0, kernel-rt-debug-kvm 5.14.0-70.144.1.rt21.216.el9_0, kernel-rt-debug-core 5.14.0-70.144.1.rt21.216.el9_0, +4 more Red Hat Enterprise Linux Real Time E4S (v.9.0) kernel-rt 5.14.0-70.144.1.rt21.216.el9_0, kernel-rt-core 5.14.0-70.144.1.rt21.216.el9_0, kernel-rt-modules 5.14.0-70.144.1.rt21.216.el9_0, kernel-rt-debug-core 5.14.0-70.144.1.rt21.216.el9_0, kernel-rt-debug-modules 5.14.0-70.144.1.rt21.216.el9_0, kernel-rt-modules-extra 5.14.0-70.144.1.rt21.216.el9_0, +2 more
    fixed: vendor fix RHSA-2025:14749
  • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt 5.14.0-284.134.1.rt14.419.el9_2, kernel-rt-core 5.14.0-284.134.1.rt14.419.el9_2, kernel-rt-modules 5.14.0-284.134.1.rt14.419.el9_2, kernel-rt-debug-core 5.14.0-284.134.1.rt14.419.el9_2, kernel-rt-modules-core 5.14.0-284.134.1.rt14.419.el9_2, kernel-rt-debug-modules 5.14.0-284.134.1.rt14.419.el9_2, +4 more Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt 5.14.0-284.134.1.rt14.419.el9_2, kernel-rt-kvm 5.14.0-284.134.1.rt14.419.el9_2, kernel-rt-core 5.14.0-284.134.1.rt14.419.el9_2, kernel-rt-modules 5.14.0-284.134.1.rt14.419.el9_2, kernel-rt-debug-kvm 5.14.0-284.134.1.rt14.419.el9_2, kernel-rt-debug-core 5.14.0-284.134.1.rt14.419.el9_2, +6 more
    fixed: vendor fix RHSA-2025:14691
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.64.1.rt7.405.el8_10, kernel-rt-core 4.18.0-553.64.1.rt7.405.el8_10, kernel-rt-modules 4.18.0-553.64.1.rt7.405.el8_10, kernel-rt-debug-core 4.18.0-553.64.1.rt7.405.el8_10, kernel-rt-debug-modules 4.18.0-553.64.1.rt7.405.el8_10, kernel-rt-modules-extra 4.18.0-553.64.1.rt7.405.el8_10, +2 more
    fixed: vendor fix RHSA-2025:11851
  • Red Hat Enterprise Linux RT (v. 9) kernel-rt 5.14.0-427.13.1.el9_4, kernel-rt-core 5.14.0-427.13.1.el9_4, kernel-rt-modules 5.14.0-427.13.1.el9_4, kernel-rt-debug-core 5.14.0-427.13.1.el9_4, kernel-rt-modules-core 5.14.0-427.13.1.el9_4, kernel-rt-debug-modules 5.14.0-427.13.1.el9_4, +4 more
    fixed: vendor fix RHSA-2024:2394
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 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

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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

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.