CVE-2026-111816: Flaw in Apache Traffic Server Scores 9.3 on CVSS
A newly published critical vulnerability in Apache Traffic Server carries a CVSS score of 9.3. Here is what is affected and how to respond.
Key points
- CVE-2026-111816 affects Apache Traffic Server.
- CVSS 9.3 (Critical).
- No exploitation confirmed yet.
Apache Traffic Server is affected by CVE-2026-111816, a security flaw that the National Vulnerability Database rates 9.3 out of 10.
At a glance
- CVE
- CVE-2026-111816
- Product
- Apache Traffic Server
- CVSS
- 9.3 Critical
- Weakness
- CWE-444
- Exploited
- No known exploitation
What is the vulnerability?
The NVD entry states: Apache Traffic Server forwarded a malformed 302 response that should have been rejected as a parse error, because the Transfer-Encoding: chunked carve-out bypassed the rejection path. A response that two peers can read differently is then stored and served, allowing cache poisoning and response-framing desync.
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.
Affected versions
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache Traffic Server | up to 8.1.11, up to 9.2.15, up to 10.1.4, 10.2.0 |
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N.
Is it being exploited?
There is no public confirmation of exploitation at the time of publication. It does not appear in CISA's Known Exploited Vulnerabilities catalog. We will update this report if that changes.
What should you do?
- Identify whether the affected product and versions run in your environment.
- Apply the vendor update listed in the advisory as soon as it is available.
- Limit network exposure of the affected service until it is patched.
- Monitor the vendor advisory for updated guidance or exploitation reports.
What to do and how to stay safe: CVE-2026-111816
- Vulnerability severity scores ignore your specific architecture and context.
- Exploitability depends on network exposure and user behavior, not just code flaws.
- Prioritization requires continuous asset inventory and threat intelligence alignment.
Risk-based vulnerability management focuses your limited resources on the flaws that actually threaten your business. Start by mapping your critical assets and checking for active exploits to prioritize your backlog.
Step-by-step guide: Risk-Based Vulnerability Management: Prioritize Fixes by Actual Danger
General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is CVE-2026-111816?
CVE-2026-111816 is a CWE-444 vulnerability in Apache Traffic Server.
How severe is CVE-2026-111816?
It has a CVSS score of 9.3 Critical.
Is CVE-2026-111816 being exploited?
There is no public confirmation of exploitation at the time of publication.
