9.1

CVE-2026-61398: apache software foundation apache cloudstack Improper Encoding or Escaping of Output

CVSS: 9.1v3.1CriticalAnalyzed
Published 21-08-2026Last modified 25-08-2026
Open JSON

Vulnerability summary

CVE-2026-61398 is a critical (CVSS 9.1) Improper Encoding or Escaping of Output vulnerability in apache software foundation apache cloudstack. EPSS estimates a 0.57% chance of exploitation in the next 30 days, higher than 45.9% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.1/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.57%
0%100%
Low · +0.25 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 21-08-2026
    PublishedVulnerability first disclosed.
  2. 25-08-2026
    Last modifiedVulnerability information updated.

Description

Improper Encoding or Escaping of Output vulnerability in Apache CloudStack's UI while using Instance Reset Password functionality. This issue affects Apache CloudStack: from 4.15.1.0 through 4.20.3.0 and from 4.21.0.0 through 4.22.1.0. Users are recommended to upgrade to version 4.20.3.1 or 4.22.1.1 or later, which fixes the issue.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.57%

Chance of exploitation in the next 30 days

Percentile

46%

Versus all other CVEs

30-day change

+0.25 pp

From 0.32% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.57%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Apache1 product
  • cloudstack≥ 4.15.1.0, < 4.20.3.1 | ≥ 4.21.0.0, < 4.22.1.1
Apache software foundation1 product

2 vendors · 2 products

References

1 links