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Fencer Vulns
medium 6.5

CVE-2017-2666 json

Undertow-core vulnerable to HTTP Request Smuggling

published 2018-07-27 8 y ago modified 2026-06-17 4 mo ago also GHSA-mcfm-h73v-635m , EUVD-2018-0639

cvss
6.5
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
3.1%
EPSS 3.1% chance of exploitation in 30 days, percentile 87%
public exploits
0
none known

Summary

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.

Patch / fix

  • maven io.undertow:undertow-core 1.3.31, 1.4.17
  • undertow Debian 14 1.4.18-1

debian advisories DEBIAN-CVE-2017-2666

  • eap7-jboss-ec2-eap jboss enterprise application platform 7 7.0.6-1.GA_redhat_1.ep7.el6
  • eap7-jboss-ec2-eap jboss enterprise application platform 7 7.0.6-1.GA_redhat_1.ep7.el7
  • eap7-jboss-ec2-eap-samples jboss enterprise application platform 7 7.0.6-1.GA_redhat_1.ep7.el6
  • eap7-jboss-ec2-eap-samples jboss enterprise application platform 7 7.0.6-1.GA_redhat_1.ep7.el7
  • eap7-wss4j jboss enterprise application platform 7 2.1.8-2.redhat_1.1.ep7.el7
  • eap7-wildfly jboss enterprise application platform 7 7.0.6-4.GA_redhat_2.1.ep7.el7
  • eap7-resteasy jboss enterprise application platform 7 3.0.19-5.SP3_redhat_1.1.ep7.el7
  • eap7-undertow jboss enterprise application platform 7 1.3.28-4.Final_redhat_4.1.ep7.el7

red hat advisories RHSA-2017:1412RHSA-2017:1411RHSA-2017:1410RHSA-2017:3458RHSA-2017:3455RHSA-2017:3454

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2017-2666 updated cvss 6.5

undertow: HTTP Request smuggling vulnerability due to permitting invalid characters in HTTP requests

  • Red Hat JBoss Fuse 6 wildfly-undertow
    affected: no fix planned “Will not fix”
  • Red Hat JBoss EAP 7.0
    fixed: vendor fix RHSA-2017:1409
  • Red Hat JBoss EAP 7.1
    fixed: vendor fix RHSA-2017:3456
  • Red Hat JBoss Enterprise Application Platform 7.0 for RHEL 6 Server eap7-wss4j 2.1.8-2.redhat_1.1.ep7.el6, eap7-wildfly 7.0.6-4.GA_redhat_2.1.ep7.el6, eap7-apache-cxf 3.1.10-2.redhat_1.1.ep7.el6, eap7-wss4j-policy 2.1.8-2.redhat_1.1.ep7.el6, eap7-resteasy 3.0.19-5.SP3_redhat_1.1.ep7.el6, eap7-apache-cxf-rt 3.1.10-2.redhat_1.1.ep7.el6, +99 more
    fixed: vendor fix RHSA-2017:1410
  • Red Hat JBoss Enterprise Application Platform 7.0 for RHEL 7 Server eap7-wss4j 2.1.8-2.redhat_1.1.ep7.el7, eap7-wildfly 7.0.6-4.GA_redhat_2.1.ep7.el7, eap7-apache-cxf 3.1.10-2.redhat_1.1.ep7.el7, eap7-wss4j-policy 2.1.8-2.redhat_1.1.ep7.el7, eap7-resteasy 3.0.19-5.SP3_redhat_1.1.ep7.el7, eap7-apache-cxf-rt 3.1.10-2.redhat_1.1.ep7.el7, +99 more
    fixed: vendor fix RHSA-2017:1412
  • Red Hat JBoss Enterprise Application Platform 7.1 for RHEL 6 Server eap7-ecj 4.6.1-1.redhat_1.1.ep7.el6, eap7-vdx 1.1.6-1.redhat_1.1.ep7.el6, eap7-xom 1.2.10-2.redhat_1.1.ep7.el6, eap7-jaxen 1.1.6-3.redhat_1.1.ep7.el6, eap7-jsoup 1.8.3-3.redhat_2.1.ep7.el6, eap7-antlr 2.7.7-35.redhat_7.1.ep7.el6, +281 more
    fixed: vendor fix RHSA-2017:3454
  • Red Hat JBoss Enterprise Application Platform 7.1 for RHEL 7 Server eap7-ecj 4.6.1-1.redhat_1.1.ep7.el7, eap7-vdx 1.1.6-1.redhat_1.1.ep7.el7, eap7-xom 1.2.10-2.redhat_1.1.ep7.el7, eap7-jaxen 1.1.6-3.redhat_1.1.ep7.el7, eap7-jsoup 1.8.3-3.redhat_2.1.ep7.el7, eap7-antlr 2.7.7-35.redhat_7.1.ep7.el7, +281 more
    fixed: vendor fix RHSA-2017:3458
  • Red Hat Single Sign-On 7 wildfly-undertow
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.09% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.0 6.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD 3.0 6.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:P/A:N
GitHub 3.0 6.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
maven io.undertow:undertow-core
<1.3.31
>=1.4.0, <1.4.17
1.3.31
1.4.17

Affected products

  • [UNKNOWN] undertow

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.