CVE-2021-4213Network attack vector

Service interruption via TLS reference cycle

Published Aug 24, 2022 · Updated Aug 3, 2024

Memory leakage in Dogtag PKI Network Security Services for Java allows remote attackers to exhaust server RAM through repeated TLS connections. JSSEngineReferenceImpl creates cyclic references through SSLAlertEvent.engine, preventing garbage collection and retaining ssl_fd, read_buf, write_buf, and JNI resources after each connection. Unauthenticated network access to a JSS-backed TLS service is sufficient; sustained connections can invoke the Linux out-of-memory process and interrupt the hosting service.

CVSS severity7.5
High
EPSS probability1.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leakage in Dogtag PKI Network Security Services for Java allows remote attackers to exhaust server RAM through repeated TLS connections. JSSEngineReferenceImpl creates cyclic references through SSLAlertEvent.engine, preventing garbage collection and retaining ssl_fd, read_buf, write_buf, and JNI resources after each connection. Unauthenticated network access to a JSS-backed TLS service is sufficient; sustained connections can invoke the Linux out-of-memory process and interrupt the hosting service.

The record

CVE
CVE-2021-4213
Published
Aug 24, 2022
Updated
Aug 3, 2024
Vendor
Dogtag PKI
Product
Network Security Services for Java (JSS)
Classifications
CWE-401, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 24, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=Fixed in v5.2.0-beta1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Dogtag PKI · Network Security Services for Java (JSS)version=Fixed in v5.2.0-beta1

Published CVSS scores

7.5NIST NVDCVSS: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.

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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-401Missing Release of Memory after Effective Lifetime
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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