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CVE-2026-55455

Appsmith server-side request forgery (SSRF)

9.1 CRITICALEPSS 0.39%
  1. Published24 Jun 2026

Description

Appsmith is a platform to build admin panels, internal tools, and dashboards. Prior to 2.1, the outbound HTTP host filter applied by WebClientUtils (used by the REST API and GraphQL datasource plugins) validates hosts against an exact-match string denylist. The comprehensive address-class check (loopback, any-local, link-local, fc00::/7) exists only on a separate code path used by SMTP, not by the HTTP plugin path. As a result, an authenticated user can craft outbound requests that reach loopback-bound services inside the container. This vulnerability is fixed in 2.1.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

Appsmith< 2.1

Remediation

Fixed in
Appsmith≥ 2.1

References

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Frequently asked

Is CVE-2026-55455 being actively exploited?

CVE-2026-55455 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.39%.

How severe is CVE-2026-55455?

CVE-2026-55455 has a CVSS 3.1 base score of 9.1, rated critical. EPSS estimates a 0.39% probability of exploitation.

Which products are affected by CVE-2026-55455?

Affected products include Appsmith.

How do I fix CVE-2026-55455?

Upgrade affected software to a fixed version, for example Appsmith 2.1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-55455 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.