CVE-2021-42010Network attack vector

Log forgery via unescaped log statements

Published Oct 24, 2022 · Updated May 7, 2025

CRLF injection in Apache Heron 0.20.4-incubating and earlier allows remote attackers to forge log entries through crafted input. Apache identifies unescaped log statements as the mechanism but has not published the affected functions or input fields. Network reachability to an input that reaches an affected statement is required; forged entries can mislead downstream log analysis.

CVSS severity9.8
Critical
EPSS probability1.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CRLF injection in Apache Heron 0.20.4-incubating and earlier allows remote attackers to forge log entries through crafted input. Apache identifies unescaped log statements as the mechanism but has not published the affected functions or input fields. Network reachability to an input that reaches an affected statement is required; forged entries can mislead downstream log analysis.

The record

CVE
CVE-2021-42010
Published
Oct 24, 2022
Updated
May 7, 2025
Vendor
The Apache Software Foundation
Product
Apache Heron
Classifications
CWE-116, T1565.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 24, 2022CVE publishedPublication date reported by the CVE source.
  2. May 7, 2025Record 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=Apache Heron 0.20.4-incubating <=0.20.4-incubating

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Heronversion=Apache Heron 0.20.4-incubating <=0.20.4-incubating

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-116Improper Encoding or Escaping of Output
T1565.001Stored Data Manipulation

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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