How severe is CVE-2021-37759?

CVE-2021-37759 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-37759 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-37759?

CVE-2021-37759 affects Graylog. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-37759?

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

When was CVE-2021-37759 published?

CVE-2021-37759 was published on 2021-07-31 and last updated on 2026-06-17.

CVE-2021-37759

CVE-2021-37759 is a critical-severity vulnerability in Graylog with a CVSS 3.x base score of 9.8. 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-532.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-532
Affected product: Graylog
Published: 2021-07-31
Last modified: 2026-06-17

Description

A Session ID leak in the DEBUG log file in Graylog before 4.1.2 allows attackers to escalate privileges (to the access level of the leaked session ID).

Frequently asked questions

What is CVE-2021-37759?: A Session ID leak in the DEBUG log file in Graylog before 4.1.2 allows attackers to escalate privileges (to the access level of the leaked session ID).
How severe is CVE-2021-37759?: CVE-2021-37759 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-37759 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-37759?: CVE-2021-37759 affects Graylog. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-37759?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-37759 published?: CVE-2021-37759 was published on 2021-07-31 and last updated on 2026-06-17.

References

https://www.graylog.org/post/announcing-graylog-v4-1-2

Affected products (1)

cpe:2.3:a:graylog:graylog:*:*:*:*:*:*:*:*

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