htmly Custom Field post cross site scripting

published 2025-09-21 13 mo ago modified 2026-10-19 20 d ago also EUVD-2025-30369

cvss: 2.4; 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 23%
public exploits: 0; none known

A security vulnerability has been detected in htmly up to 3.1.0. The impacted element is an unknown function of the file /htmly/admin/field/post of the component Custom Field Handler. Such manipulation of the argument label leads to cross site scripting. The attack can be launched remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 13 mo ago (2025-09-22)

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

notion.so https://www.notion.so/inmog/Reported-Vulnerability-XSS-Vulnerability-in-htmly-v3-1-0-2627752d1edd804fbd71f310bde44d11 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	4.8	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
CNA	3.1	2.4	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA	3.0	2.4	CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA	2.0	3.3	AV:N/AC:L/Au:M/C:N/I:P/A:N/E:POC/RL:ND/RC:UR
CNA	4.0	1.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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	2.4	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N
NVD	3.1	4.8	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
CNA	2.0	3.3	AV:N/AC:L/Au:M/C:N/I:P/A:N

Affected products

n/a htmly

Classification

Weakness

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

References

notion.so /inmog/Reported-Vulnerability-XSS-Vulnerability-in-htmly-v3-1-0-2627752d1edd804fbd71f310bde44d11
exploit, third-party-advisory
vuldb.com /?id.325113
vdb-entry, technical-description, third-party-advisory
vuldb.com /?ctiid.325113
signature, permissions-required, vdb-entry
vuldb.com /?submit.645806
third-party-advisory, vdb-entry

Sources

CVE List CVE-2025-10758
NVD CVE-2025-10758

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