MaxBoard XSS and File Upload Vulnerability

published 2022-04-26 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-13422

cvss: 8.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.8%; EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits: 0; none known

Insufficient script validation of the admin page enables XSS, which causes unauthorized users to steal admin privileges. When uploading file in a specific menu, the verification of the files is insufficient. It allows remote attackers to upload arbitrary files disguising them as image files.

Patch / fix

fixed in 1

maxb maxboard 1.9.6.1

Exploit prediction

0.79% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
NVD	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

No Vendor Information MaxBoard

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation
CWE-434 Unrestricted Upload of File with Dangerous Type

References

krcert.or.kr /krcert/secNoticeView.do?bulletin_writing_sequence=66673
third-party-advisory

Sources

CVE List CVE-2021-26628
NVD CVE-2021-26628

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