How severe is CVE-2026-2967?

CVE-2026-2967 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 none, and availability low.

Is CVE-2026-2967 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-2967?

CVE-2026-2967 affects Cesanta Mongoose. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-2967?

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

Does CVE-2026-2967 have an EU (EUVD) identifier?

Yes. CVE-2026-2967 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7603.

When was CVE-2026-2967 published?

CVE-2026-2967 was published on 2026-02-23 and last updated on 2026-06-17.

CVE-2026-2967

CVE-2026-2967 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-940.

Key facts

Severity: Low (CVSS 3.x base score 3.7)
CVSS v2: 2.6
CVSS v4: 2.9
EPSS exploit prediction: 0% (39th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-7603
Weakness: CWE-940
Affected product: Cesanta Mongoose
Published: 2026-02-23
Last modified: 2026-06-17

Description

A security vulnerability has been detected in Cesanta Mongoose up to 7.20. This affects the function getpeer of the file /src/net_builtin.c of the component TCP Sequence Number Handler. The manipulation leads to improper verification of source of a communication channel. The attack may be initiated remotely. The attack's complexity is rated as high. The exploitability is reported as difficult. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Frequently asked questions

What is CVE-2026-2967?: A security vulnerability has been detected in Cesanta Mongoose up to 7.20. This affects the function getpeer of the file /src/net_builtin.c of the component TCP Sequence Number Handler. The manipulation leads to improper verification of source of a communication channel. The attack may be initiated remotely. The attack's complexity is rated as high. The exploitability is reported as difficult. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
How severe is CVE-2026-2967?: CVE-2026-2967 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 none, and availability low.
Is CVE-2026-2967 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-2967?: CVE-2026-2967 affects Cesanta Mongoose. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-2967?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-2967 have an EU (EUVD) identifier?: Yes. CVE-2026-2967 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7603.
When was CVE-2026-2967 published?: CVE-2026-2967 was published on 2026-02-23 and last updated on 2026-06-17.

References

Affected products (1)

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

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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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