CVE-2021-29725Network attack vector

Service interruption via unreleased remote resources

Published Jul 15, 2021 · Updated Sep 16, 2024

Resource leakage in affected IBM Sterling authentication and proxy servers allows remote attackers to exhaust resources and interrupt service. IBM identifies External Authentication Server 2.4.3.2, 6.0.1, and 6.0.2 and Secure Proxy 3.4.3.2, 6.0.1, and 6.0.2, but does not disclose the leaking object, handler, or request. Unauthenticated network access is sufficient, and the published consequence is limited to resource exhaustion and service interruption.

CVSS severity7.5
High
EPSS probability2.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource leakage in affected IBM Sterling authentication and proxy servers allows remote attackers to exhaust resources and interrupt service. IBM identifies External Authentication Server 2.4.3.2, 6.0.1, and 6.0.2 and Secure Proxy 3.4.3.2, 6.0.1, and 6.0.2, but does not disclose the leaking object, handler, or request. Unauthenticated network access is sufficient, and the published consequence is limited to resource exhaustion and service interruption.

The record

CVE
CVE-2021-29725
Published
Jul 15, 2021
Updated
Sep 16, 2024
Vendor
IBM
Product
IBM Sterling Secure Proxy
Classifications
CWE-770, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=3.4.3.2
  2. Affected versionversion=6.0.1
  3. Affected versionversion=6.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

IBM · IBM Sterling Secure Proxyversion=3.4.3.2; version=6.0.1; version=6.0.2
IBM · IBM Sterling External Authentication Serverversion=2.4.3.2; version=6.0.1; version=6.0.2

Published CVSS scores

6.5IBMCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
7.5IBMCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-770Allocation of Resources Without Limits or Throttling
T1499Endpoint Denial of Service

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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