How severe is CVE-2021-43521?

CVE-2021-43521 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-2021-43521 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43521?

CVE-2021-43521 affects Zlog Project Zlog. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43521?

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-2021-43521 published?

CVE-2021-43521 was published on 2022-04-08 and last updated on 2026-06-17.

CVE-2021-43521

CVE-2021-43521 is a high-severity vulnerability in Zlog Project Zlog 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-787.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (66th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Zlog Project Zlog
Published: 2022-04-08
Last modified: 2026-06-17

Description

A Buffer Overflow vulnerability exists in zlog 1.2.15 via zlog_conf_build_with_file in src/zlog/src/conf.c.

Frequently asked questions

What is CVE-2021-43521?: A Buffer Overflow vulnerability exists in zlog 1.2.15 via zlog_conf_build_with_file in src/zlog/src/conf.c.
How severe is CVE-2021-43521?: CVE-2021-43521 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-2021-43521 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43521?: CVE-2021-43521 affects Zlog Project Zlog. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43521?: 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-2021-43521 published?: CVE-2021-43521 was published on 2022-04-08 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:zlog_project:zlog:1.2.15:*:*:*:*:*:*:*

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