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Fencer Intel
medium 5.5

CVE-2024-26603 json

x86/fpu: Stop relying on userspace for info to fault in xsave buffer

published 2y ago modified 4mo ago also EUVD-2024-23865

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 20%
public exploits
0
none known

Summary

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

x86/fpu: Stop relying on userspace for info to fault in xsave buffer

Before this change, the expected size of the user space buffer was taken from fx_sw->xstate_size. fx_sw->xstate_size can be changed from user-space, so it is possible construct a sigreturn frame where:

* fx_sw->xstate_size is smaller than the size required by valid bits in fx_sw->xfeatures. * user-space unmaps parts of the sigrame fpu buffer so that not all of the buffer required by xrstor is accessible.

In this case, xrstor tries to restore and accesses the unmapped area which results in a fault. But fault_in_readable succeeds because buf + fx_sw->xstate_size is within the still mapped area, so it goes back and tries xrstor again. It will spin in this loop forever.

Instead, fault in the maximum size which can be touched by XRSTOR (taken from fpstate->user_size).

[ dhansen: tweak subject / changelog ]

Patch / fix

  • Linux Linux 5.15.150, 6.1.79, 6.6.18, 6.7.6, 6.8
  • linux Debian 12 6.1.82-1
  • linux Debian 14, Debian 13 6.7.7-1

debian advisories DEBIAN-CVE-2024-26603

  • linux Ubuntu 22.04 LTS 5.15.0-112.122
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1063.69
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1062.70
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1060.66
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1056.59
  • linux-kvm Ubuntu 22.04 LTS 5.15.0-1060.65
  • linux-azure Ubuntu 22.04 LTS 5.15.0-1066.75
  • linux-gkeop Ubuntu 22.04 LTS 5.15.0-1046.53

ubuntu advisories UBUNTU-CVE-2024-26603

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-2025:2490RHSA-2024:9315RHSA-2024:3627RHSA-2024:3618

  • kernel-rt SLE Micro 5.4, SLE Micro 5.3, openSUSE Leap Micro 5.4 +1 more 5.14.21-150400.15.71.1
  • kernel-source-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.71.1
  • kernel-rt SLE Micro 5.5, Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.38.1
  • kernel-syms-rt Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.38.1
  • kernel-rt_debug Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.38.1
  • kernel-source-rt SLE Micro 5.5, Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.38.1
  • kernel-syms SLE High Performance Computing 15 SP4-ESPOS, Manager Server 4.3, Manager Proxy 4.3 +3 more 5.14.21-150400.24.111.1
  • kernel-source SLE High Performance Computing 15 SP4-ESPOS, Manager Server 4.3, Manager Proxy 4.3 +3 more 5.14.21-150400.24.111.1

suse advisories SUSE-SU-2024:0977-1SUSE-SU-2024:0910-1SUSE-SU-2024:0900-2SUSE-SU-2024:0900-1SUSE-SU-2024:0858-1SUSE-SU-2024:0855-1

  • kernel AlmaLinux 8 4.18.0-553.5.1.el8_10
  • perf AlmaLinux 8 4.18.0-553.5.1.el8_10
  • bpftool AlmaLinux 8 4.18.0-553.5.1.el8_10
  • kernel-core AlmaLinux 8 4.18.0-553.5.1.el8_10
  • kernel-tools AlmaLinux 8 4.18.0-553.5.1.el8_10
  • python3-perf AlmaLinux 8 4.18.0-553.5.1.el8_10
  • kernel-modules AlmaLinux 8 4.18.0-553.5.1.el8_10
  • kernel-zfcpdump AlmaLinux 8 4.18.0-553.5.1.el8_10

almalinux advisories ALSA-2024:3618ALSA-2024:3627

  • kernel-rt Rocky Linux 8 4.18.0-553.5.1.rt7.346.el8_10
  • kernel Rocky Linux 8 4.18.0-553.5.1.el8_10

rocky linux advisories RLSA-2024:3627RLSA-2024:3618

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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-2024-26603 updated cvss 5.5

kernel: x86/fpu: Stop relying on userspace for info to fault in xsave buffer that cause loop forever

  • 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
    fixed: vendor fix RHSA-2024:9315
  • Red Hat CodeReady Linux Builder EUS (v.9.4) libperf 5.14.0-427.59.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.59.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.59.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.59.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.59.1.el9_4
    fixed: vendor fix RHSA-2025:2490
  • 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
    fixed: vendor fix RHSA-2024:9315
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) rv 5.14.0-427.59.1.el9_4, perf 5.14.0-427.59.1.el9_4, rtla 5.14.0-427.59.1.el9_4, kernel-devel-matched 5.14.0-427.59.1.el9_4, kernel-64k-devel-matched 5.14.0-427.59.1.el9_4, kernel-debug-devel-matched 5.14.0-427.59.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:2490
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.5.1.el8_10, kernel 4.18.0-553.5.1.el8_10, bpftool 4.18.0-553.5.1.el8_10, kernel-core 4.18.0-553.5.1.el8_10, kernel-tools 4.18.0-553.5.1.el8_10, python3-perf 4.18.0-553.5.1.el8_10, +15 more
    fixed: vendor fix RHSA-2024:3618
  • 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
    fixed: vendor fix RHSA-2024:9315
  • Red Hat Enterprise Linux BaseOS EUS (v.9.4) bpftool 7.3.0-427.59.1.el9_4, kernel 5.14.0-427.59.1.el9_4, kernel-64k 5.14.0-427.59.1.el9_4, kernel-core 5.14.0-427.59.1.el9_4, kernel-tools 5.14.0-427.59.1.el9_4, python3-perf 5.14.0-427.59.1.el9_4, +28 more
    fixed: vendor fix RHSA-2025:2490
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.5.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.5.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.5.1.el8_10
    fixed: vendor fix RHSA-2024:3618
show 7 more
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-kvm 4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-core 4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-modules 4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-debug-kvm 4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-debug-core 4.18.0-553.5.1.rt7.346.el8_10, +4 more
    fixed: vendor fix RHSA-2024:3627
  • 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
    fixed: vendor fix RHSA-2024:9315
  • Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt 5.14.0-427.59.1.el9_4, kernel-rt-core 5.14.0-427.59.1.el9_4, kernel-rt-modules 5.14.0-427.59.1.el9_4, kernel-rt-debug-core 5.14.0-427.59.1.el9_4, kernel-rt-modules-core 5.14.0-427.59.1.el9_4, kernel-rt-debug-modules 5.14.0-427.59.1.el9_4, +4 more
    fixed: vendor fix RHSA-2025:2490
  • 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 Enterprise Linux Real Time for NFV EUS (v.9.4) kernel-rt 5.14.0-427.59.1.el9_4, kernel-rt-kvm 5.14.0-427.59.1.el9_4, kernel-rt-core 5.14.0-427.59.1.el9_4, kernel-rt-modules 5.14.0-427.59.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.59.1.el9_4, kernel-rt-debug-core 5.14.0-427.59.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:2490
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-core 4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-modules 4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-debug-core 4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-debug-modules 4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-modules-extra 4.18.0-553.5.1.rt7.346.el8_10, +2 more
    fixed: vendor fix RHSA-2024:3627
  • 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 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 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
2y ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-11).

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

Weakness
  • CWE-835 Loop with Unreachable Exit Condition
Technology feeds

References

Sources

Fencer Intel 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.