CVE-2026-50131Public exploitNetwork attack vector

SSRF via incomplete special-use IPv4 validation

Published Jun 10, 2026 · Updated Jun 10, 2026

SSRF in Fedify and vocab-runtime allows remote attackers to make affected servers request special-use IPv4 destinations. The isValidPublicIPv4Address() helper behind validatePublicUrl() returns true for carrier-grade NAT, benchmarking, multicast, reserved, and other non-public ranges. Exploitation requires an affected application to process an attacker-controlled ActivityPub document or media URL and exposes resources reachable through those routes.

CVSS severity8.6
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Fedify and vocab-runtime allows remote attackers to make affected servers request special-use IPv4 destinations. The isValidPublicIPv4Address() helper behind validatePublicUrl() returns true for carrier-grade NAT, benchmarking, multicast, reserved, and other non-public ranges. Exploitation requires an affected application to process an attacker-controlled ActivityPub document or media URL and exposes resources reachable through those routes.

The record

CVE
CVE-2026-50131
Published
Jun 10, 2026
Updated
Jun 10, 2026
Vendor
Fedify
Product
Fedify
Classifications
CWE-1389, CWE-918, CWE-1286, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 10, 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=>= 0.11.2, < 1.9.12
  2. Affected versionversion=>= 1.10.0, < 1.10.11
  3. Affected versionversion=>= 2.0.0, < 2.0.19
  4. Affected versionversion=>= 2.1.0, < 2.1.15
  5. Affected versionversion=>= 2.2.0, < 2.2.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fedify · Fedifyversion=>= 0.11.2, < 1.9.12; version=>= 1.10.0, < 1.10.11; version=>= 2.0.0, < 2.0.19; version=>= 2.1.0, < 2.1.15; version=>= 2.2.0, < 2.2.4
Fedify · vocab-runtimeversion=< 2.0.19; version=>= 2.1.0, < 2.1.15; version=>= 2.2.0, < 2.2.4

Published CVSS scores

8.6Fedify GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1389Incorrect Parsing of Numbers with Different Radices
CWE-918Server-Side Request Forgery (SSRF)
CWE-1286Improper Validation of Syntactic Correctness of Input
T1190Exploit Public-Facing Application

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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