CVE-2026-41293High· 7.3▾ MidnightPoC availableApache Tomcat did not validate HTTP/2 request headers, triggering unexpected application behavior, as applications may presume that header values exposed through the Servlet API would be valid.
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 40.2 · likelihood 0.3 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Public exploit / PoC code seen in 1 source. Availability, not in-the-wild use.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the vendor's CSAF advisory record, not NVD.
Exploit-prediction probability, daily snapshots since Sep 17.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CSAF
1.7%
9.8 → 7.3
critical → high
Last analysed / modified upstream
1 GitHub repo (last check)
Apache Tomcat did not validate HTTP/2 request headers, triggering unexpected application behavior, as applications may presume that header values exposed through the Servlet API would be valid.
tomcat-coyote: Apache Tomcat: HTTP/2 request headers not validated — rated Moderate by Red Hat. Released 2026-05-12, updated 2026-09-21.
Affected:
Fixed:
No fix planned:
Not affected:
Before applying this update, make sure all previously released errata relevant to your system have been applied.
For details on how to apply this update, refer to:
https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:43401 Before applying this update, make sure all previously released errata relevant to your system have been applied.
For details on how to apply this update, refer to:
https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:39188 For details on how to apply this update, which includes the changes described in this advisory, refer to:
https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:67164
Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
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