CVE-2021-29749Network attack vector

SSRF via unrestricted document type definitions

Published Jul 15, 2021 · Updated Sep 17, 2024

SSRF in IBM Sterling Secure Proxy and External Authentication Server 6.0.2 allows remote authenticated users to issue unauthorized requests. The products accept unrestricted document type definitions, enabling attacker-controlled XML references to trigger server-side network requests; IBM has not named the input interface or parser. Authenticated access is required, and the requests can enumerate internal networks or facilitate request-based follow-on attacks.

CVSS severity5.4
Medium
EPSS probability0.83%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in IBM Sterling Secure Proxy and External Authentication Server 6.0.2 allows remote authenticated users to issue unauthorized requests. The products accept unrestricted document type definitions, enabling attacker-controlled XML references to trigger server-side network requests; IBM has not named the input interface or parser. Authenticated access is required, and the requests can enumerate internal networks or facilitate request-based follow-on attacks.

The record

CVE
CVE-2021-29749
Published
Jul 15, 2021
Updated
Sep 17, 2024
Vendor
IBM
Product
IBM Sterling Secure Proxy
Classifications
CWE-918, T1046
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=6.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

IBM · IBM Sterling Secure Proxyversion=6.0.2
IBM · IBM Sterling External Authentication Serverversion=6.0.2

Published CVSS scores

5.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:N
6.5IBM CorporationCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1046Network Service Discovery

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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