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Fencer Vulns
medium 5.5

CVE-2026-63004 json

Unleash: Addon webhook URL is dialed server-side with no internal-address filtering, enabling SSRF to internal services / cloud metadata and exfiltration of configured request headers

published 2026-08-21 2 mo ago modified 2026-10-14 25 d ago also GHSA-5vf6-jrqr-78fj , EUVD-2026-64040

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits
0
none known

Summary

Unleash is an open-source feature management platform. Prior to 7.5.2, 7.6.5, and 8.0.2, the addon and integration subsystem passes the operator-controlled parameters.url value from src/lib/addons/webhook.ts and the Slack, Microsoft Teams, Datadog, and New Relic integrations to Addon.fetchRetry in src/lib/addons/addon.ts without restricting loopback, link-local, private, or cloud metadata addresses. An authenticated actor with the root CREATE_ADDON or UPDATE_ADDON permission can cause the server to send requests from inside its network boundary, use integration event status as a blind probing oracle, forward Authorization, customHeaders, or DD-API-KEY values to an attacker-observed host, and deliver the feature-event JSON body to internal services. This issue is fixed in versions 7.5.2, 7.6.5, and 8.0.2.

Patch / fix

  • npm unleash-server 7.5.2, 7.6.5, 8.0.2

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/Unleash/unleash/security/advisories/GHSA-5vf6-jrqr-78fj referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.5 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
GitHub 3.1 5.5 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm unleash-server
<7.5.2
>=7.6.0, <7.6.5
>=8.0.0, <8.0.2
7.5.2
7.6.5
8.0.2

Affected products

  • Unleash unleash

Classification

Weakness
  • CWE-918 Server-Side Request Forgery

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.