No exploitation reportedFix available

CVE-2021-42010

Q: What is CVE-2021-42010?

Heron versions <= 0.20.4-incubating allows CRLF log injection because of the lack of escaping in the log statements. Please update to version 0.20.5-incubating which addresses this issue.

Q: Is CVE-2021-42010 actively exploited?

Active exploitation of CVE-2021-42010 has not been confirmed. Its EPSS score was 1.8% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-42010?

CVE-2021-42010 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2022-10-24
Fixed in0.20.5-incubating
WeaknessCWE-116

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Heron versions <= 0.20.4-incubating allows CRLF log injection because of the lack of escaping in the log statements. Please update to version 0.20.5-incubating which addresses this issue.

Timeline

dates in UTC

2022-10-2414:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-42010?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-42010?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Apache heron

Branch	Affected	Fixed in	Source
0.20	< 0.20.5-incubating	0.20.5-incubating	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Apache heron to 0.20.5-incubating

Advisories and patches

lists.apache.orgVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2025-05-07
OpenCVESSVC decisionnone—
CISA-ADPCVSS 3.19.82025-05-07
NVDCVSS 3.19.8read 2026-10-23
CISA-ADPweakness (CWE)CWE-1162025-05-07
NVDweakness (CWE)CWE-116read 2026-10-23
FIRST EPSSEPSS score1.8 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2022-10-24
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-42010?

Heron versions <= 0.20.4-incubating allows CRLF log injection because of the lack of escaping in the log statements. Please update to version 0.20.5-incubating which addresses this issue.

Is CVE-2021-42010 actively exploited?

Active exploitation of CVE-2021-42010 has not been confirmed. Its EPSS score was 1.8% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-42010?

CVE-2021-42010 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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