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Fencer Vulns
medium 5.5

CVE-2022-49081 json

highmem: fix checks in __kmap_local_sched_{in,out}

published 2025-02-26 20 mo ago modified 2026-06-17 4 mo ago also EUVD-2022-55123

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

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

highmem: fix checks in __kmap_local_sched_{in,out}

When CONFIG_DEBUG_KMAP_LOCAL is enabled __kmap_local_sched_{in,out} check that even slots in the tsk->kmap_ctrl.pteval are unmapped. The slots are initialized with 0 value, but the check is done with pte_none. 0 pte however does not necessarily mean that pte_none will return true. e.g. on xtensa it returns false, resulting in the following runtime warnings:

WARNING: CPU: 0 PID: 101 at mm/highmem.c:627 __kmap_local_sched_out+0x51/0x108 CPU: 0 PID: 101 Comm: touch Not tainted 5.17.0-rc7-00010-gd3a1cdde80d2-dirty #13 Call Trace: dump_stack+0xc/0x40 __warn+0x8f/0x174 warn_slowpath_fmt+0x48/0xac __kmap_local_sched_out+0x51/0x108 __schedule+0x71a/0x9c4 preempt_schedule_irq+0xa0/0xe0 common_exception_return+0x5c/0x93 do_wp_page+0x30e/0x330 handle_mm_fault+0xa70/0xc3c do_page_fault+0x1d8/0x3c4 common_exception+0x7f/0x7f

WARNING: CPU: 0 PID: 101 at mm/highmem.c:664 __kmap_local_sched_in+0x50/0xe0 CPU: 0 PID: 101 Comm: touch Tainted: G W 5.17.0-rc7-00010-gd3a1cdde80d2-dirty #13 Call Trace: dump_stack+0xc/0x40 __warn+0x8f/0x174 warn_slowpath_fmt+0x48/0xac __kmap_local_sched_in+0x50/0xe0 finish_task_switch$isra$0+0x1ce/0x2f8 __schedule+0x86e/0x9c4 preempt_schedule_irq+0xa0/0xe0 common_exception_return+0x5c/0x93 do_wp_page+0x30e/0x330 handle_mm_fault+0xa70/0xc3c do_page_fault+0x1d8/0x3c4 common_exception+0x7f/0x7f

Fix it by replacing !pte_none(pteval) with pte_val(pteval) != 0.

Patch / fix

  • Linux Linux 5.15.34, 5.16.20, 5.17.3, 5.18
  • linux Debian 14, Debian 13, Debian 12 5.17.3-1

debian advisories DEBIAN-CVE-2022-49081

  • linux Ubuntu 22.04 LTS 5.15.0-37.39
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1011.14
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1008.12
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1008.10
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1007.8
  • linux-kvm Ubuntu 22.04 LTS 5.15.0-1010.11
  • linux-azure Ubuntu 22.04 LTS 5.15.0-1010.12
  • linux-raspi Ubuntu 22.04 LTS 5.15.0-1011.13

ubuntu advisories UBUNTU-CVE-2022-49081

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 8 4.18.0-553.el8_10
  • perf RHEL 8 4.18.0-553.el8_10
  • bpftool RHEL 8 4.18.0-553.el8_10
  • kernel-core RHEL 8 4.18.0-553.el8_10
  • kernel-tools RHEL 8 4.18.0-553.el8_10
  • python3-perf RHEL 8 4.18.0-553.el8_10
  • kernel-modules RHEL 8 4.18.0-553.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.el8_10

red hat advisories RHSA-2024:3138RHSA-2023:2458

  • kernel Rocky Linux 8 4.18.0-553.123.1.el8_10.cloud.0.1

rocky linux advisories RXSA-2024:3138

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-2022-49081 updated cvss 3.3

kernel: highmem: fix checks in __kmap_local_sched_{in,out}

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +6 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) perf 5.14.0-284.11.1.el9_2, rtla 5.14.0-284.11.1.el9_2, kernel-devel-matched 5.14.0-284.11.1.el9_2, kernel-64k-devel-matched 5.14.0-284.11.1.el9_2, kernel-debug-devel-matched 5.14.0-284.11.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.11.1.el9_2, +5 more
    fixed: vendor fix RHSA-2023:2458
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.el8_10, kernel 4.18.0-553.el8_10, bpftool 4.18.0-553.el8_10, kernel-core 4.18.0-553.el8_10, kernel-tools 4.18.0-553.el8_10, python3-perf 4.18.0-553.el8_10, +15 more
    fixed: vendor fix RHSA-2024:3138
  • Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.0.0-284.11.1.el9_2, kernel 5.14.0-284.11.1.el9_2, kernel-64k 5.14.0-284.11.1.el9_2, kernel-core 5.14.0-284.11.1.el9_2, kernel-tools 5.14.0-284.11.1.el9_2, python3-perf 5.14.0-284.11.1.el9_2, +28 more
    fixed: vendor fix RHSA-2023:2458
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.el8_10
    fixed: vendor fix RHSA-2024:3138
  • Red Hat Enterprise Linux CRB (v. 9) kernel-debuginfo-common-s390x 5.14.0-284.11.1.el9_2, kernel-debuginfo-common-x86_64 5.14.0-284.11.1.el9_2, kernel-debuginfo-common-aarch64 5.14.0-284.11.1.el9_2, kernel-debuginfo-common-ppc64le 5.14.0-284.11.1.el9_2
    fixed: vendor fix RHSA-2023:2458
  • 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

0.25% chance of exploitation in the next 30 days, higher than 15% 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.