How severe is CVE-2017-2921?

CVE-2017-2921 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-2017-2921 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-2921?

CVE-2017-2921 affects Cesanta Mongoose. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2017-2921?

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-2017-2921 published?

CVE-2017-2921 was published on 2017-11-07 and last updated on 2026-06-17.

CVE-2017-2921

CVE-2017-2921 is a critical-severity vulnerability in Cesanta Mongoose 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-190.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Cesanta Mongoose
Published: 2017-11-07
Last modified: 2026-06-17

Description

An exploitable memory corruption vulnerability exists in the Websocket protocol implementation of Cesanta Mongoose 6.8. A specially crafted websocket packet can cause an integer overflow, leading to a heap buffer overflow and resulting in denial of service and potential remote code execution. An attacker needs to send a specially crafted websocket packet over network to trigger this vulnerability.

Frequently asked questions

What is CVE-2017-2921?: An exploitable memory corruption vulnerability exists in the Websocket protocol implementation of Cesanta Mongoose 6.8. A specially crafted websocket packet can cause an integer overflow, leading to a heap buffer overflow and resulting in denial of service and potential remote code execution. An attacker needs to send a specially crafted websocket packet over network to trigger this vulnerability.
How severe is CVE-2017-2921?: CVE-2017-2921 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-2017-2921 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-2921?: CVE-2017-2921 affects Cesanta Mongoose. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-2921?: 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-2017-2921 published?: CVE-2017-2921 was published on 2017-11-07 and last updated on 2026-06-17.

References

https://www.talosintelligence.com/vulnerability_reports/TALOS-2017-0428

Affected products (1)

cpe:2.3:a:cesanta:mongoose:6.8:*:*:*:*:*:*:*

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CVE-2015-5097 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
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