CVE-2026-111808
Apache Traffic Server: HTTP/2 DATA frame padding underflow lets a client trigger backend worker-pool exhaustion
Apache Software Foundation Apache Traffic Server
CVSS
8.6HighExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.32%Chance of exploitation activity in the next 30 days, higher than 24% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
What fixes it
No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.
Description
Apache Traffic Server can be used to exhaust an HTTP/1.1 origin's worker pool via a malformed padded HTTP/2 DATA frame.
This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.15, from 10.0.0 through 10.1.4, 10.2.0.
Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue.
Text from CVE List
Affected versions 4
- Apache Traffic Serveraffected: 8.0.0 through 8.1.11CVE List
- Apache Traffic Serveraffected: 9.0.0 through 9.2.15CVE List
- Apache Traffic Serveraffected: 10.0.0 through 10.1.4CVE List
- Apache Traffic Serveraffected: 10.2.0CVE List