CVE-2026-61398

Q: How do I fix CVE-2026-61398?

Upgrade cloudstack to 4.20.3.1 or later.

Q: Is CVE-2026-61398 being actively exploited?

Not that we know of. CVE-2026-61398 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.32% is the estimated probability that it will be exploited in the next 30 days. That is higher than 24% of all scored CVEs.

Q: How severe is CVE-2026-61398?

CVE-2026-61398 has a CVSS v3 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2026-61398 affect?

Published advisories record a fix for cloudstack (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

CRITICAL

9.1

CVSS v3

NVD

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.

CWE-116

How to fix

Remediation Available

cloudstackNVD

Affected:>= 4.15.1.0, < 4.20.3.1Fixed in:4.20.3.1CVE-2026-61398derived from NVD

Affected:>= 4.21.0.0, < 4.22.1.1Fixed in:4.22.1.1CVE-2026-61398derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploit Intelligence

0.32%probability of exploitation in 30 days

24thpercentile

Low risk: more likely to be exploited than 24% of all known CVEs.

References

Vendor Advisory1

lists.apache.org

Related Vulnerabilities

Other CWE-116 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-38475	Critical	9.1	100%	KEV	Fix
CVE-2022-36446	Critical	9.8	96%	-	Fix
CVE-2021-31806	Medium	6.5	96%	-	Fix
CVE-2022-30781	High	7.5	89%	-	Fix
CVE-2022-36099	Critical	9.9	76%	-	Fix
CVE-2022-36100	Critical	9.9	74%	-	Fix

Common questions

How do I fix CVE-2026-61398?

Upgrade cloudstack to 4.20.3.1 or later.

Is CVE-2026-61398 being actively exploited?

Not that we know of. CVE-2026-61398 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.32% is the estimated probability that it will be exploited in the next 30 days. That is higher than 24% of all scored CVEs.

How severe is CVE-2026-61398?

CVE-2026-61398 has a CVSS v3 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-61398 affect?

Published advisories record a fix for cloudstack (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

Embed a live status badge for CVE-2026-61398

Markdown

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-27.