CVE-2026-31818Public exploitNetwork attack vector

Authenticated SSRF via empty default IP blacklist

Published Apr 3, 2026 · Updated Apr 3, 2026

Server-side request forgery in Budibase before 3.33.4 allows remote authenticated users to access internal services via REST queries. The backend-core isBlacklisted function returns false when BLACKLIST_IPS is unset, so the REST connector fetches attacker-selected internal URLs. Builder access, or QUERY WRITE permission on an existing query, is required; reachable services can be read or modified through their HTTP APIs.

CVSS severity9.6
Critical
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Server-side request forgery in Budibase before 3.33.4 allows remote authenticated users to access internal services via REST queries. The backend-core isBlacklisted function returns false when BLACKLIST_IPS is unset, so the REST connector fetches attacker-selected internal URLs. Builder access, or QUERY WRITE permission on an existing query, is required; reachable services can be read or modified through their HTTP APIs.

The record

CVE
CVE-2026-31818
Published
Apr 3, 2026
Updated
Apr 3, 2026
Vendor
Budibase
Product
Budibase
Classifications
CWE-918, CWE-1188, T1090.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.33.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Budibase · Budibaseversion=< 3.33.4

Published CVSS scores

9.6GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
9.9NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
CWE-1188Initialization of a Resource with an Insecure Default
T1090.001Internal Proxy

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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