How severe is CVE-2023-34188?

CVE-2023-34188 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-2023-34188 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-34188?

CVE-2023-34188 affects Cesanta Mongoose. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-34188?

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-2023-34188 published?

CVE-2023-34188 was published on 2023-06-23 and last updated on 2026-06-17.

CVE-2023-34188

CVE-2023-34188 is a high-severity vulnerability in Cesanta Mongoose 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-1284.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1284
Affected product: Cesanta Mongoose
Published: 2023-06-23
Last modified: 2026-06-17

Description

The HTTP server in Mongoose before 7.10 accepts requests containing negative Content-Length headers. By sending a single attack payload over TCP, an attacker can cause an infinite loop in which the server continuously reparses that payload, and does not respond to any other requests.

Frequently asked questions

What is CVE-2023-34188?: The HTTP server in Mongoose before 7.10 accepts requests containing negative Content-Length headers. By sending a single attack payload over TCP, an attacker can cause an infinite loop in which the server continuously reparses that payload, and does not respond to any other requests.
How severe is CVE-2023-34188?: CVE-2023-34188 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-2023-34188 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-34188?: CVE-2023-34188 affects Cesanta Mongoose. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-34188?: 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-2023-34188 published?: CVE-2023-34188 was published on 2023-06-23 and last updated on 2026-06-17.

References

Affected products (1)

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

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