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TI-2021-13030 Aliases CVE-2021-33656GHSA-9p9r-j677-3r3q

When setting font with malicous data by ioctl cmd PIO_FONT,kernel will write memory out of bounds.

Priority LOW 33CWE-787Published · Updated

Key facts

Attack vector
Physical
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 7 fixed, 3 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-787 and the CVSS impact.

Summary

When setting font with malicous data by ioctl cmd PIO_FONT,kernel will write memory out of bounds.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00611 49th percentileScored 2026-11-07
Fix Partial openEuler:kernel: 5.10.127Red Hat: 3 advisoriesRed Hat: 7 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
—openEuler:kernelbefore 5.10.1275.10.127Patch availableCNA
  • openEuler:kernel Vendor— Affected before 5.10.127 Fixed in 5.10.127 Patch available CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:o:openatom:openeuler:20.03:-:*:*:lts:*:*:*20.03VulnerableOpenatom
cpe:2.3:o:openatom:openeuler:20.03:sp1:*:*:lts:*:*:*20.03 sp1VulnerableOpenatom
cpe:2.3:o:openatom:openeuler:20.03:sp3:*:*:lts:*:*:*20.03 sp3VulnerableOpenatom
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*before 5.10.127VulnerableLinux
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*10.0VulnerableDebian
  • cpe:2.3:o:openatom:openeuler:20.03:-:*:*:lts:*:*:* Versions 20.03 Vulnerable ·Openatom
  • cpe:2.3:o:openatom:openeuler:20.03:sp1:*:*:lts:*:*:* Versions 20.03 sp1 Vulnerable ·Openatom
  • cpe:2.3:o:openatom:openeuler:20.03:sp3:*:*:lts:*:*:* Versions 20.03 sp3 Vulnerable ·Openatom
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions before 5.10.127 Vulnerable ·Linux
  • cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian

Remediation

  • Fix · CNA openEuler:kernel Fixed in 5.10.127

Red Hat 3 advisories

  • RHSA-2023:4789 Released 2023-08-29 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder EUS (v.8.6) kernel-tools-libs-devel-4.18.0-372.70.1.el8_6
    • Red Hat Enterprise Linux BaseOS EUS (v.8.6) bpftool-4.18.0-372.70.1.el8_6, kernel-4.18.0-372.70.1.el8_6, kernel-abi-stablelists-4.18.0-372.70.1.el8_6 +19
    • Red Hat Virtualization 4 Hypervisor for RHEL 8 kernel-devel-4.18.0-372.70.1.el8_6, perf-4.18.0-372.70.1.el8_6
  • RHSA-2023:2951 Released 2023-05-16 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-477.10.1.el8_8, kernel-4.18.0-477.10.1.el8_8, kernel-abi-stablelists-4.18.0-477.10.1.el8_8 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-477.10.1.el8_8
  • RHSA-2023:2736 Released 2023-05-16 · Red Hat rating Important
    kernel-rt security and bug fix update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-477.10.1.rt7.274.el8_8, kernel-rt-core-4.18.0-477.10.1.rt7.274.el8_8, kernel-rt-debug-4.18.0-477.10.1.rt7.274.el8_8 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-477.10.1.rt7.274.el8_8, kernel-rt-core-4.18.0-477.10.1.rt7.274.el8_8, kernel-rt-debug-4.18.0-477.10.1.rt7.274.el8_8 +7

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat CodeReady Linux Builder EUS (v.8.6)Fixed RHSA-2023:4789
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2023:2951
Red Hat Enterprise Linux BaseOS EUS (v.8.6)Fixed RHSA-2023:4789
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2023:2951
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2023:2736
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2023:2736
Red Hat Virtualization 4 Hypervisor for RHEL 8Fixed RHSA-2023:4789
Not affected: 1 product
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-33656
  2. 2026-10-03 Alias added: GHSA-9p9r-j677-3r3q
  3. 2026-10-08 CISA SSVC decision points changed

References

Patch 2

Advisory 2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences