How severe is CVE-2025-63656?

CVE-2025-63656 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-2025-63656 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-63656?

CVE-2025-63656 affects Monkey-project Monkey. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-63656?

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.

Does CVE-2025-63656 have an EU (EUVD) identifier?

Yes. CVE-2025-63656 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206524.

When was CVE-2025-63656 published?

CVE-2025-63656 was published on 2026-01-29 and last updated on 2026-06-17.

CVE-2025-63656

CVE-2025-63656 is a high-severity vulnerability in Monkey-project Monkey 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-125.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-206524
Weakness: CWE-125
Affected product: Monkey-project Monkey
Published: 2026-01-29
Last modified: 2026-06-17

Description

An out-of-bounds read in the header_cmp function (mk_server/mk_http_parser.c) of monkey commit f37e984 allows attackers to cause a Denial of Service (DoS) via sending a crafted HTTP request to the server.

Frequently asked questions

What is CVE-2025-63656?: An out-of-bounds read in the header_cmp function (mk_server/mk_http_parser.c) of monkey commit f37e984 allows attackers to cause a Denial of Service (DoS) via sending a crafted HTTP request to the server.
How severe is CVE-2025-63656?: CVE-2025-63656 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-2025-63656 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-63656?: CVE-2025-63656 affects Monkey-project Monkey. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-63656?: 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.
Does CVE-2025-63656 have an EU (EUVD) identifier?: Yes. CVE-2025-63656 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206524.
When was CVE-2025-63656 published?: CVE-2025-63656 was published on 2026-01-29 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:monkey-project:monkey:*:*:*:*:*:*:*:*

More vulnerabilities in Monkey-project Monkey

CVE-2013-2159 — Critical (CVSS 9.8): Monkey HTTP Daemon: broken user name authentication
CVE-2025-63658 — High (CVSS 7.5): A stack overflow in the mk_http_index_lookup function (mk_server/mk_http.c) of monkey commit f37e984 allows attackers…
CVE-2025-63657 — High (CVSS 7.5): An out-of-bounds read in the mk_mimetype_find function (mk_server/mk_mimetype.c) of monkey commit f37e984 allows…
CVE-2025-63655 — High (CVSS 7.5): A NULL pointer dereference in the mk_http_range_parse function (mk_server/mk_http.c) of monkey commit f37e984 allows…
CVE-2025-63653 — High (CVSS 7.5): An out-of-bounds read in the mk_vhost_fdt_close function (mk_server/mk_vhost.c) of monkey commit f37e984 allows…
CVE-2025-63652 — High (CVSS 7.5): A use-after-free in the mk_http_request_end function (mk_server/mk_http.c) of monkey commit f37e984 allows attackers to…

All CVEs affecting Monkey-project Monkey →

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