CVE-2026-77762: Apache Tomcat: Stale HPACK emitter injects trailers into recycled pooled Request
Apache Software Foundation · Apache Tomcat
Vendor fix available · Affected: Apache Software Foundation Apache Tomcat · Exploitation: not established
ExploitationNot established
Not in CISA KEV as of catalogue 2026.11.13 (13 Nov)
- In CISA KEV: not seen
- Exploited (reported): not seen
- Scanning observed: not seen
- Proof of concept public: not seen
- Not establishedNothing in the sources we check
Higher than 40% of scored CVEs
Not scored yet. NVD has not published a CVSS score.
DescriptionNVD
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in Apache Tomcat allows an attacker to inject trailer fields into another HTTP/2 request. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.39 through 9.0.121. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.59 through 8.5.100. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.26, 10.1.60, 9.0.122, which fix the issue.
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Weakness
- Race Condition · Race Conditions
- Published
- September 2026
Coverage1 article · 1 outlet
First in our coverage: SecurityOnline, 23 Sep.
- Apache Tomcat 11.0.26 Fixes 15 Flaws Enabling Request Smuggling and DoSSecurityOnline · first in our coverage · mentions it in passing
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