8.7

CVE-2025-53634: Chall-Manager's HTTP Gateway have no header check timeout leading to potential slow loris attacks

Analyzed
AliasesGHSA-ggmv-j932-q89qGO-2025-3809
Published 10-07-2025Last modified 10-07-2025

Vulnerability summary

CVE-2025-53634 is a high (CVSS 8.7) vulnerability in ctfer-io chall-manager. EPSS estimates a 0.51% chance of exploitation in the next 30 days, higher than 43.4% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 8.7 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
8.7/10
010
High · v4.0 (CVE.org)
EPSS score
0.51%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
OPENSUSE-SU-2025:15405-1

Timeline

  1. 10-07-2025
    PublishedVulnerability first disclosed.
  2. 10-07-2025
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 3 sources · 2 versions

EPSS trend

Probability

0.51%

Chance of exploitation in the next 30 days

Percentile

43%

Versus all other CVEs

30-day change

Increase +0.02 pp

From 0.49% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ctfer-io1 product
Github.com/ctfer-io1 product
  • chall-manager< 0.1.4

2 vendors · 2 products

References

5 links