CVE-2026-16027Network attack vector

SSRF via unauthenticated WebSocket-to-XAdES requests

Published Aug 7, 2026 · Updated Aug 7, 2026

SSRF in Gelir İdaresi Başkanlığı E-Signature allows remote attackers to issue network requests through its local signing client. The CNA identifies an unauthenticated WebSocket-to-XAdES request path in versions starting at 2.4.4.0 and before 2.5.1.0, but published sources disclose neither the controlled field, request sink, nor missing validation. User interaction is required; successful requests can read or modify data, while no service interruption is reported.

CVSS severity5.4
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

SSRF in Gelir İdaresi Başkanlığı E-Signature allows remote attackers to issue network requests through its local signing client. The CNA identifies an unauthenticated WebSocket-to-XAdES request path in versions starting at 2.4.4.0 and before 2.5.1.0, but published sources disclose neither the controlled field, request sink, nor missing validation. User interaction is required; successful requests can read or modify data, while no service interruption is reported.

The record

CVE
CVE-2026-16027
Published
Aug 7, 2026
Updated
Aug 7, 2026
Vendor
Gelir İdaresi Başkanlığı
Product
E-Signature
Classifications
CWE-918, CAPEC-664, T1090
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 7, 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=2.4.4.0 <2.5.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Gelir İdaresi Başkanlığı · E-Signatureversion=2.4.4.0 <2.5.1.0

Published CVSS scores

5.4TR-CERTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A: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.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
CAPEC-664Server Side Request Forgery
T1090Proxy

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo