How severe is CVE-2026-86243?

CVE-2026-86243 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-86243 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-86243?

CVE-2026-86243 affects Apache Tomcat Native. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-86243?

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

When was CVE-2026-86243 published?

CVE-2026-86243 was published on 2026-09-23 and last updated on 2026-10-06.

CVE-2026-86243

CVE-2026-86243 is a high-severity vulnerability in Apache Tomcat Native with a CVSS 3.x base score of 7.5. 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-126.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (32nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-126
Affected product: Apache Tomcat Native
Published: 2026-09-23
Last modified: 2026-10-06

Description

Buffer over-read vulnerability in Apache Tomcat Native during the TLS handshake permits a malicious user to trigger a DoS via a JVM crash. This issue affects Apache Tomcat Native: from 2.0.0 through 2.0.15, from 1.3.0 through 1.3.8. Earlier, unsupported versions may also be affected. Users are recommended to upgrade to version 1.3.9 or 2.0.16, which fix the issue.

Frequently asked questions

What is CVE-2026-86243?: Buffer over-read vulnerability in Apache Tomcat Native during the TLS handshake permits a malicious user to trigger a DoS via a JVM crash. This issue affects Apache Tomcat Native: from 2.0.0 through 2.0.15, from 1.3.0 through 1.3.8. Earlier, unsupported versions may also be affected. Users are recommended to upgrade to version 1.3.9 or 2.0.16, which fix the issue.
How severe is CVE-2026-86243?: CVE-2026-86243 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-86243 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-86243?: CVE-2026-86243 affects Apache Tomcat Native. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-86243?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-86243 published?: CVE-2026-86243 was published on 2026-09-23 and last updated on 2026-10-06.

References

Affected products (1)

cpe:2.3:a:apache:tomcat_native:*:*:*:*:*:*:*:*

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