CVE-2026-8606Network attack vector

Secret disclosure via unvalidated package name SSRF

Published May 26, 2026 · Updated May 27, 2026

SSRF in GitHub Enterprise Server before 3.21.1 allows remote attackers to infer sensitive environment variables through package lookup requests. The package URL endpoint accepts a supplied package name without validation and issues requests to internal services, exposing values through response timing. GitHub Packages must be enabled; access is unauthenticated when private mode is disabled and otherwise requires any authenticated account.

CVSS severity7.0
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in GitHub Enterprise Server before 3.21.1 allows remote attackers to infer sensitive environment variables through package lookup requests. The package URL endpoint accepts a supplied package name without validation and issues requests to internal services, exposing values through response timing. GitHub Packages must be enabled; access is unauthenticated when private mode is disabled and otherwise requires any authenticated account.

The record

CVE
CVE-2026-8606
Published
May 26, 2026
Updated
May 27, 2026
Vendor
Twitter
Product
GitHub Enterprise Server
Classifications
CWE-918, CAPEC-492, CAPEC-664, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 26, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 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=3.16.0 <=3.16.18 changes=[{"at":"3.16.19","status":"unaffected"}]
  2. Affected versionversion=3.17.0 <=3.17.15 changes=[{"at":"3.17.16","status":"unaffected"}]
  3. Affected versionversion=3.18.0 <=3.18.9 changes=[{"at":"3.18.10","status":"unaffected"}]
  4. Affected versionversion=3.19.0 <=3.19.6 changes=[{"at":"3.19.7","status":"unaffected"}]
  5. Affected versionversion=3.20.0 <=3.20.2 changes=[{"at":"3.20.3","status":"unaffected"}]
  6. Affected versionversion=3.21.0 <3.21.1 changes=[{"at":"3.21.1","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Twitter · GitHub Enterprise Serverversion=3.16.0 <=3.16.18 changes=[{"at":"3.16.19","status":"unaffected"}]; version=3.17.0 <=3.17.15 changes=[{"at":"3.17.16","status":"unaffected"}]; version=3.18.0 <=3.18.9 changes=[{"at":"3.18.10","status":"unaffected"}]; version=3.19.0 <=3.19.6 changes=[{"at":"3.19.7","status":"unaffected"}]; version=3.20.0 <=3.20.2 changes=[{"at":"3.20.3","status":"unaffected"}]; version=3.21.0 <3.21.1 changes=[{"at":"3.21.1","status":"unaffected"}]

Published CVSS scores

5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
7.0GitHub, Inc. (Products Only)CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N

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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
CAPEC-492Regular Expression Exponential Blowup
CAPEC-664Server Side Request Forgery
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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