How severe is CVE-2026-65637?

CVE-2026-65637 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-2026-65637 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-65637?

CVE-2026-65637 affects Apache Tomcat. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-65637?

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-2026-65637 published?

CVE-2026-65637 was published on 2026-08-25 and last updated on 2026-08-27.

CVE-2026-65637

CVE-2026-65637 is a critical-severity vulnerability in Apache Tomcat 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-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Apache Tomcat
Published: 2026-08-25
Last modified: 2026-08-27

Description

Improper Input Validation vulnerability in Apache Tomcat due to incomplete fix for CVE-2026-32990. This issue affects Apache Tomcat: from 11.0.20 through 11.0.24, from 10.1.53 through 10.1.57, from 9.0.115 through 9.0.120. Users are recommended to upgrade to version 11.0.25, 10.1.58 or 9.0.121, which fix the issue.

Frequently asked questions

What is CVE-2026-65637?: Improper Input Validation vulnerability in Apache Tomcat due to incomplete fix for CVE-2026-32990. This issue affects Apache Tomcat: from 11.0.20 through 11.0.24, from 10.1.53 through 10.1.57, from 9.0.115 through 9.0.120. Users are recommended to upgrade to version 11.0.25, 10.1.58 or 9.0.121, which fix the issue.
How severe is CVE-2026-65637?: CVE-2026-65637 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-2026-65637 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-65637?: CVE-2026-65637 affects Apache Tomcat. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-65637?: 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-2026-65637 published?: CVE-2026-65637 was published on 2026-08-25 and last updated on 2026-08-27.

References

https://lists.apache.org/thread/djog953z1ohsyt25bdvhfzbmsy22vgcj

Affected products (1)

cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*

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