How severe is CVE-2021-38604?

CVE-2021-38604 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-38604 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-38604?

CVE-2021-38604 primarily affects Gnu Glibc. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-38604?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-38604 published?

CVE-2021-38604 was published on 2021-08-12 and last updated on 2026-06-17.

CVE-2021-38604

CVE-2021-38604 is a high-severity vulnerability in Gnu Glibc with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Gnu Glibc
Published: 2021-08-12
Last modified: 2026-06-17

Description

In librt in the GNU C Library (aka glibc) through 2.34, sysdeps/unix/sysv/linux/mq_notify.c mishandles certain NOTIFY_REMOVED data, leading to a NULL pointer dereference. NOTE: this vulnerability was introduced as a side effect of the CVE-2021-33574 fix.

Frequently asked questions

What is CVE-2021-38604?: In librt in the GNU C Library (aka glibc) through 2.34, sysdeps/unix/sysv/linux/mq_notify.c mishandles certain NOTIFY_REMOVED data, leading to a NULL pointer dereference. NOTE: this vulnerability was introduced as a side effect of the CVE-2021-33574 fix.
How severe is CVE-2021-38604?: CVE-2021-38604 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-38604 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-38604?: CVE-2021-38604 primarily affects Gnu Glibc. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-38604?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-38604 published?: CVE-2021-38604 was published on 2021-08-12 and last updated on 2026-06-17.

References

Affected products (11)

cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_cloud_native_core_binding_support_function:22.1.3:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment:22.1.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:22.1.2:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:22.2.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_cloud_native_core_security_edge_protection_proxy:22.1.1:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_cloud_native_core_unified_data_repository:22.2.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:enterprise_operations_monitor:4.3:*:*:*:*:*:*:*
cpe:2.3:a:oracle:enterprise_operations_monitor:4.4:*:*:*:*:*:*:*
cpe:2.3:a:oracle:enterprise_operations_monitor:5.0:*:*:*:*:*:*:*

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