CVE-2017-2666
MEDIUMEPSS 85th pctlDescription
It was discovered in Undertow that the code that parsed the HTTP request line permitted invalid characters. This could be exploited, in conjunction with a proxy that also permitted the invalid characters but with a different interpretation, to inject data into the HTTP response. By manipulating the HTTP response the attacker could poison a web-cache, perform an XSS attack, or obtain sensitive information from requests other than their own.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Exploit Intelligence
Elevated risk: more likely to be exploited than 85% of all known CVEs.
References
Related Vulnerabilities
Other CWE-444 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-22536 | Critical | 10.0 | 98% | KEV | - |
| CVE-2025-61884 | High | 7.5 | 98% | KEV + Ransom | - |
| CVE-2020-9490 | High | 7.5 | 90% | - | Fix |
| CVE-2023-41265 | Critical | 9.6 | 84% | KEV + Ransom | - |
| CVE-2023-25690 | Critical | 9.8 | 84% | - | Fix |
| CVE-2022-32214 | Medium | 6.5 | 81% | - | Fix |
Common questions
How do I fix CVE-2017-2666?
Upgrade undertow on debian unstable to 1.4.18-1 or later.
Is CVE-2017-2666 being actively exploited?
Not that we know of. CVE-2017-2666 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 2.7% is the estimated probability that it will be exploited in the next 30 days. That is higher than 85% of all scored CVEs.
How severe is CVE-2017-2666?
CVE-2017-2666 has a CVSS v3 base score of 6.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2017-2666 affect?
Published advisories record a fix for undertow (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.