How severe is CVE-2021-43466?

CVE-2021-43466 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-43466 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43466?

CVE-2021-43466 affects Thymeleaf. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43466?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-43466 published?

CVE-2021-43466 was published on 2021-11-09 and last updated on 2026-06-17.

CVE-2021-43466

CVE-2021-43466 is a critical-severity vulnerability in Thymeleaf with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 6.8
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-94
Affected product: Thymeleaf
Published: 2021-11-09
Last modified: 2026-06-17

Description

In the thymeleaf-spring5:3.0.12 component, thymeleaf combined with specific scenarios in template injection may lead to remote code execution.

Frequently asked questions

What is CVE-2021-43466?: In the thymeleaf-spring5:3.0.12 component, thymeleaf combined with specific scenarios in template injection may lead to remote code execution.
How severe is CVE-2021-43466?: CVE-2021-43466 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-43466 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43466?: CVE-2021-43466 affects Thymeleaf. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43466?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-43466 published?: CVE-2021-43466 was published on 2021-11-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:thymeleaf:thymeleaf:3.0.12:*:*:*:*:*:*:*

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