Gnuboard g6 Post Reply qa cross site scripting

published 2025-07-18 15 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-21881

cvss: 3.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits: 0; none known

A vulnerability, which was classified as problematic, has been found in Gnuboard g6 up to 6.0.10. This issue affects some unknown processing of the file /bbs/scrap_popin_update/qa/ of the component Post Reply Handler. The manipulation leads to cross site scripting. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 15 mo ago (2025-07-18)

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/gnuboard/g6/issues/645 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
CNA	3.1	3.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA	3.0	3.5	CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA	2.0	4.0	AV:N/AC:L/Au:S/C:N/I:P/A:N/E:POC/RL:ND/RC:UR
CNA	4.0	2.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/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
CNA	3.1	3.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
NVD	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CNA	2.0	4.0	AV:N/AC:L/Au:S/C:N/I:P/A:N

Affected products

Gnuboard g6

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation
CWE-94 Improper Control of Generation of Code

References

github.com /gnuboard/g6/issues/645
exploit, issue-tracking
vuldb.com /?id.316847
vdb-entry, third-party-advisory
vuldb.com /?ctiid.316847
signature, permissions-required, vdb-entry
vuldb.com /?submit.615735
third-party-advisory, vdb-entry

Sources

CVE List CVE-2025-7786
NVD CVE-2025-7786

Fencer Vulns 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.

Summary