How severe is CVE-2025-53634?

CVE-2025-53634 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-2025-53634 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-53634?

CVE-2025-53634 affects Ctfer-io Chall-manager. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-53634?

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-2025-53634 have an EU (EUVD) identifier?

Yes. CVE-2025-53634 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21052.

When was CVE-2025-53634 published?

CVE-2025-53634 was published on 2025-07-10 and last updated on 2026-06-17.

CVE-2025-53634

CVE-2025-53634 is a high-severity vulnerability in Ctfer-io Chall-manager 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-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.7
EPSS exploit prediction: 0% (36th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-21052
Weakness: CWE-770
Affected product: Ctfer-io Chall-manager
Published: 2025-07-10
Last modified: 2026-06-17

Description

Chall-Manager is a platform-agnostic system able to start Challenges on Demand of a player. The HTTP Gateway processes headers, but with no timeout set. With a slow loris attack, an attacker could cause Denial of Service (DoS). Exploitation does not require authentication nor authorization, so anyone can exploit it. It should nonetheless not be exploitable as it is highly recommended to bury Chall-Manager deep within the infrastructure due to its large capabilities, so no users could reach the system. Patch has been implemented by commit 1385bd8 and shipped in v0.1.4.

Frequently asked questions

What is CVE-2025-53634?: Chall-Manager is a platform-agnostic system able to start Challenges on Demand of a player. The HTTP Gateway processes headers, but with no timeout set. With a slow loris attack, an attacker could cause Denial of Service (DoS). Exploitation does not require authentication nor authorization, so anyone can exploit it. It should nonetheless not be exploitable as it is highly recommended to bury Chall-Manager deep within the infrastructure due to its large capabilities, so no users could reach the system. Patch has been implemented by commit 1385bd8 and shipped in v0.1.4.
How severe is CVE-2025-53634?: CVE-2025-53634 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-2025-53634 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-53634?: CVE-2025-53634 affects Ctfer-io Chall-manager. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-53634?: 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-2025-53634 have an EU (EUVD) identifier?: Yes. CVE-2025-53634 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21052.
When was CVE-2025-53634 published?: CVE-2025-53634 was published on 2025-07-10 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:ctfer-io:chall-manager:*:*:*:*:*:*:*:*

More vulnerabilities in Ctfer-io Chall-manager

CVE-2026-32768 — Critical (CVSS 9.9): Chall-Manager is a platform-agnostic system able to start Challenges on Demand of a player. In versions prior to 0.6.5,…
CVE-2025-53633 — Critical (CVSS 9.8): Chall-Manager is a platform-agnostic system able to start Challenges on Demand of a player. When decoding a scenario…
CVE-2025-53632 — Critical (CVSS 9.1): Chall-Manager is a platform-agnostic system able to start Challenges on Demand of a player. When decoding a scenario…

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