CVE-2021-47157

CRITICALNVD 9.89.8—

9.8

The Kossy module before 0.60 for Perl allows JSON hijacking because of X-Requested-With mishandling.

CVSS v3: 9.8
EG Score: 9.8(medium)
EPSS: 25.1%
KEV: Not listed

Published

March 18, 2024

Last Modified

April 15, 2026

Advisory Details (2)

Auto-updated May 18, 2026

No patch confirmed yet.

generic

Client Challenge

https://metacpan.org/dist/Kossy/changes

generic

[IMCOMPATIBLE CHANGE] fix: defense from JSON hijacking by kfly8 · Pull Request #16 · kazeburo/Kossy · GitHub

https://github.com/kazeburo/Kossy/pull/16

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-346Origin Validation Error

Data Freshness Timeline

(refreshed 8× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 13:43 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
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2026-05-22 21:16 UTCepss_batch
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2026-05-22 21:16 UTCepss_batch
2026-05-22 21:16 UTCepss_batch

Frequently asked(5)

What is CVE-2021-47157?

CVE-2021-47157 is a critical vulnerability published on March 18, 2024. The Kossy module before 0.60 for Perl allows JSON hijacking because of X-Requested-With mishandling.

When was CVE-2021-47157 disclosed?

CVE-2021-47157 was first published in the National Vulnerability Database on March 18, 2024, with the most recent update on April 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-47157 actively exploited?

CVE-2021-47157 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 25.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-47157?

CVE-2021-47157 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2021-47157?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-47157, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2021-47157

📅 Published

🔄 Last Modified

📋 Advisory Details (2)