CVE-2021-20109

CVE-2021-20109 is a high-severity vulnerability in Zohocorp Manageengine Assetexplorer 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

Description

Due to the Asset Explorer agent not validating HTTPS certificates, an attacker on the network can statically configure their IP address to match the Asset Explorer's Server IP address. This will allow an attacker to send a NEWSCAN request to a listening agent on the network as well as receive the agent's HTTP request verifying its authtoken. In AEAgent.cpp, the agent responding back over HTTP is vulnerable to a Heap Overflow if the POST payload response is too large. The POST payload response is converted to Unicode using vswprintf. This is written to a buffer only 0x2000 bytes big. If POST payload is larger, then heap overflow will occur.

Frequently asked questions

What is CVE-2021-20109?
Due to the Asset Explorer agent not validating HTTPS certificates, an attacker on the network can statically configure their IP address to match the Asset Explorer's Server IP address. This will allow an attacker to send a NEWSCAN request to a listening agent on the network as well as receive the agent's HTTP request verifying its authtoken. In AEAgent.cpp, the agent responding back over HTTP is vulnerable to a Heap Overflow if the POST payload response is too large. The POST payload response is converted to Unicode using vswprintf. This is written to a buffer only 0x2000 bytes big. If POST payload is larger, then heap overflow will occur.
How severe is CVE-2021-20109?
CVE-2021-20109 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 high, and availability none.
Is CVE-2021-20109 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20109?
CVE-2021-20109 affects Zohocorp Manageengine Assetexplorer. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-20109?
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-2021-20109 published?
CVE-2021-20109 was published on 2021-07-19 and last updated on 2026-06-17.

References

Affected products (1)

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