CVE-2021-37840

CVE-2021-37840 is a high-severity vulnerability in Aapanel with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

aaPanel through 6.8.12 allows Cross-Site WebSocket Hijacking (CSWH) involving OS commands within WebSocket messages at a ws:// URL for /webssh (the victim must have configured Terminal with at least one host). Successful exploitation depends on the browser used by a potential victim (e.g., exploitation can occur with Firefox but not Chrome).

Frequently asked questions

What is CVE-2021-37840?
aaPanel through 6.8.12 allows Cross-Site WebSocket Hijacking (CSWH) involving OS commands within WebSocket messages at a ws:// URL for /webssh (the victim must have configured Terminal with at least one host). Successful exploitation depends on the browser used by a potential victim (e.g., exploitation can occur with Firefox but not Chrome).
How severe is CVE-2021-37840?
CVE-2021-37840 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-37840 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-37840?
CVE-2021-37840 affects Aapanel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-37840?
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-2021-37840 published?
CVE-2021-37840 was published on 2021-08-02 and last updated on 2026-06-17.

References

Affected products (1)

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