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TI-2021-04826 Aliases CVE-2021-21781GHSA-v4c8-84p4-cxv7

Use of uninitialized resource in Linux Kernel

Priority LOW 17CWE-908Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Information disclosure
Confidentiality · integrity · availability
Low · None · None
Fix status
Partial Red Hat: 2 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-908 and the CVSS impact.

Summary

An information disclosure vulnerability exists in the ARM SIGPAGE functionality of Linux Kernel v5.4.66 and v5.4.54. The latest version (5.11-rc4) seems to still be vulnerable. A userland application can read the contents of the sigpage, which can leak kernel memory contents. An attacker can read a process’s memory at a specific offset to trigger this vulnerability. This was fixed in kernel releases: 4.14.222 4.19.177 5.4.99 5.10.17 5.11

Why it matters now

EPSS 0.00496 42nd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Red Hat: 1 advisoryRed Hat: 2 fixed, 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
—Linux KernelLinux Kernel v5.4.54, Linux Kernel v5.4.66—No fix listedCNA
  • Linux Kernel Vendor— Affected Linux Kernel v5.4.54, Linux Kernel v5.4.66 Fixed in — No fix listed CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:5.4.54:*:*:*:*:*:*:*5.4.54VulnerableLinux
cpe:2.3:o:linux:linux_kernel:5.4.66:*:*:*:*:*:*:*5.4.66VulnerableLinux
cpe:2.3:a:oracle:communications_cloud_native_core_binding_support_function:22.1.3:*:*:*:*:*:*:*22.1.3VulnerableOracle
cpe:2.3:a:oracle:communications_cloud_native_core_network_exposure_function:22.1.1:*:*:*:*:*:*:*22.1.1VulnerableOracle
cpe:2.3:a:oracle:communications_cloud_native_core_policy:22.2.0:*:*:*:*:*:*:*22.2.0VulnerableOracle
  • cpe:2.3:o:linux:linux_kernel:5.4.54:*:*:*:*:*:*:* Versions 5.4.54 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:5.4.66:*:*:*:*:*:*:* Versions 5.4.66 Vulnerable ·Linux
  • cpe:2.3:a:oracle:communications_cloud_native_core_binding_support_function:22.1.3:*:*:*:*:*:*:* Versions 22.1.3 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_cloud_native_core_network_exposure_function:22.1.1:*:*:*:*:*:*:* Versions 22.1.1 Vulnerable ·Oracle
  • cpe:2.3:a:oracle:communications_cloud_native_core_policy:22.2.0:*:*:*:*:*:*:* Versions 22.2.0 Vulnerable ·Oracle

Remediation

Red Hat 1 advisory

  • RHSA-2022:1988 Released 2022-05-10 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-372.9.1.el8, kernel-4.18.0-372.9.1.el8, kernel-abi-stablelists-4.18.0-372.9.1.el8 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-372.9.1.el8

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 7AffectedNo fix planned: Will not fix
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2022:1988
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2022:1988
Not affected: 4 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-21781
  2. 2026-10-03 Alias added: GHSA-v4c8-84p4-cxv7

References

Exploit 1

Patch 1

Sources

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