How severe is CVE-2026-2966?

CVE-2026-2966 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-2966 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-2966?

CVE-2026-2966 affects Cesanta Mongoose. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-2966?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-2966 have an EU (EUVD) identifier?

Yes. CVE-2026-2966 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7602.

When was CVE-2026-2966 published?

CVE-2026-2966 was published on 2026-02-23 and last updated on 2026-06-17.

CVE-2026-2966

CVE-2026-2966 is a low-severity vulnerability in Cesanta Mongoose with a CVSS 3.x base score of 3.7. 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-310.

Key facts

Severity: Low (CVSS 3.x base score 3.7)
CVSS v2: 2.6
CVSS v4: 2.9
EPSS exploit prediction: 0% (30th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-7602
Weakness: CWE-310
Affected product: Cesanta Mongoose
Published: 2026-02-23
Last modified: 2026-06-17

Description

A weakness has been identified in Cesanta Mongoose up to 7.20. The impacted element is the function mg_sendnsreq of the file /src/dns.c of the component DNS Transaction ID Handler. Executing a manipulation of the argument random can lead to insufficiently random values. The attack can be launched remotely. The attack requires a high level of complexity. The exploitability is regarded as difficult. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Frequently asked questions

What is CVE-2026-2966?: A weakness has been identified in Cesanta Mongoose up to 7.20. The impacted element is the function mg_sendnsreq of the file /src/dns.c of the component DNS Transaction ID Handler. Executing a manipulation of the argument random can lead to insufficiently random values. The attack can be launched remotely. The attack requires a high level of complexity. The exploitability is regarded as difficult. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.
How severe is CVE-2026-2966?: CVE-2026-2966 has a CVSS 3.x base score of 3.7, rated low severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-2966 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-2966?: CVE-2026-2966 affects Cesanta Mongoose. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-2966?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-2966 have an EU (EUVD) identifier?: Yes. CVE-2026-2966 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7602.
When was CVE-2026-2966 published?: CVE-2026-2966 was published on 2026-02-23 and last updated on 2026-06-17.

References

Affected products (1)

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

More vulnerabilities in Cesanta Mongoose

CVE-2022-25299 — Critical (CVSS 9.8): This affects the package cesanta/mongoose before 7.6. The unsafe handling of file names during upload using…
CVE-2020-25756 — Critical (CVSS 9.8): A buffer overflow vulnerability exists in the mg_get_http_header function in Cesanta Mongoose 6.18 due to a lack of…
CVE-2019-19307 — Critical (CVSS 9.8): An integer overflow in parse_mqtt in mongoose.c in Cesanta Mongoose 6.16 allows an attacker to achieve remote DoS…
CVE-2019-12951 — Critical (CVSS 9.8): An issue was discovered in Mongoose before 6.15. The parse_mqtt() function in mg_mqtt.c has a critical heap-based…
CVE-2018-20356 — Critical (CVSS 9.8): An invalid read of 8 bytes due to a use-after-free vulnerability in the mg_http_free_proto_data_cgi function call in…
CVE-2018-20355 — Critical (CVSS 9.8): An invalid write of 8 bytes due to a use-after-free vulnerability in the mg_http_free_proto_data_cgi function call in…

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