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Response snapshot Oct 27, 2026, 16:01 UTC

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VulnerabilityCVE-2026-65637

Apache Tomcat - HTTP/2 no-authority bypass of strict SNI validation

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.

At a glance

Exploited
Not known
Severity
9.8 Critical (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: org.apache.tomcat:tomcat-coyote: 11.0.25; org.apache.tomcat:tomcat-coyote: 10.1.59; org.apache.tomcat:tomcat-coyote: 9.0.121; org.apache.tomcat.embed:tomcat-embed-core: 11.0.25; org.apache.tomcat.embed:tomcat-embed-core: 10.1.59; org.apache.tomcat.embed:tomcat-embed-core: 9.0.121. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-f525-44xv-f2qj (opens a new tab)

What happened

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, 10.1.59 or 9.0.121, which fix the issue.

Affected package ranges reported by GitHub: org.apache.tomcat:tomcat-coyote: >= 11.0.20, < 11.0.25 org.apache.tomcat:tomcat-coyote: >= 10.1.53, <= 10.1.57 org.apache.tomcat:tomcat-coyote: >= 9.0.115, < 9.0.121 org.apache.tomcat.embed:tomcat-embed-core: >= 11.0.20, < 11.0.25 org.apache.tomcat.embed:tomcat-embed-core: >= 10.1.53, <= 10.1.57 org.apache.tomcat.embed:tomcat-embed-core: >= 9.0.115, < 9.0.121

Scores and how they were measured

CVSS base severity

9.8

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-f525-44xv-f2qj (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-f525-44xv-f2qj, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 27). Apache Tomcat - HTTP/2 no-authority bypass of strict SNI validation (CVE-2026-65637). https://kevwire.com/record/CVE-2026-65637

MLA

"Apache Tomcat - HTTP/2 no-authority bypass of strict SNI validation (CVE-2026-65637)." KEVWire, 27 Oct. 2026, kevwire.com/record/CVE-2026-65637.

Chicago

KEVWire. "Apache Tomcat - HTTP/2 no-authority bypass of strict SNI validation (CVE-2026-65637)." Last modified October 27, 2026. https://kevwire.com/record/CVE-2026-65637.

Evidence summary (plain text)

Apache Tomcat - HTTP/2 no-authority bypass of strict SNI validation (Aug 26, 2026).
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.
CVSS 9.8 (version 3.1; evidence as of Oct 27, 2026; https://github.com/advisories/GHSA-f525-44xv-f2qj).
Sources:
GitHub-reviewed advisory GHSA-f525-44xv-f2qj: https://github.com/advisories/GHSA-f525-44xv-f2qj
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: CVE-2026-65637.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 27, 2026, 16:00 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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