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Fencer Intel
medium 5.3

CVE-2025-59843 json

FlagForgeCTF Exposes User Emails via Public /api/user/[username] API

published last yr. modified last mo. also EUVD-2025-31370

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits
0
none known

Summary

Flag Forge is a Capture The Flag (CTF) platform. From versions 2.0.0 to before 2.3.2, the public endpoint /api/user/[username] returns user email addresses in its JSON response. The fix, intended for release in 2.3.1 but only available starting in version 2.3.2, removes email addresses from public API responses while keeping the endpoint publicly accessible. Users should upgrade to version 2.3.2 or later to eliminate exposure. There are no workarounds for this vulnerability.

Patch / fix

  • flagforge flagforge 2.3.1

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected products

  • FlagForgeCTF flagForge

Classification

Weakness
  • CWE-359 Exposure of Private Personal Information to an Unauthorized Actor

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.