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Fencer Vulns
medium 4.8

CVE-2021-3688 json

A flaw was found in Red Hat JBoss Core Services HTTP Server in all versions, where it does not properly normalize the path component of a r…

published 2022-08-26 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-26976

cvss
4.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

A flaw was found in Red Hat JBoss Core Services HTTP Server in all versions, where it does not properly normalize the path component of a request URL contains dot-dot-semicolon(s). This flaw could allow an attacker to access unauthorized information or possibly conduct further attacks. The highest threat from this vulnerability is to data confidentiality and integrity.

Patch / fix

  • redhat jboss_core_services_httpd 2.4.37
  • jbcs-httpd24-apr jboss core services 1 1.6.3-107.jbcs.el7
  • jbcs-httpd24-apr jboss core services 1 1.6.3-107.el8jbcs
  • jbcs-httpd24-curl jboss core services 1 7.78.0-2.jbcs.el7
  • jbcs-httpd24-curl jboss core services 1 7.78.0-2.el8jbcs
  • jbcs-httpd24-httpd jboss core services 1 2.4.37-78.jbcs.el7
  • jbcs-httpd24-httpd jboss core services 1 2.4.37-78.el8jbcs
  • jbcs-httpd24-mod_jk jboss core services 1 1.2.48-20.redhat_1.jbcs.el7
  • jbcs-httpd24-mod_jk jboss core services 1 1.2.48-20.redhat_1.el8jbcs

red hat advisories RHSA-2021:4614

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-2021-3688 updated cvss 4.8

JBCS: URL normalization issue with dot-dot-semicolon(s) leads to information disclosure

  • Red Hat JBoss Enterprise Application Platform 6 httpd22 httpd22
    affected: workaround, no fix planned “Manually add LocationMatch directive to deny any possible problem requests in the JBCS httpd configuration. For example: ~~~ <LocationMatch ".*\.\.;.*"> Require all denied </LocationMatch> ~~~”
  • Red Hat JBoss Core Services
    fixed: vendor fix “Manually add LocationMatch directive to deny any possible problem requests in the JBCS httpd configuration. For example: ~~~ <LocationMatch ".*\.\.;.*"> Require all denied </LocationMatch> ~~~” RHSA-2021:4613
  • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-apr 1.6.3-107.jbcs.el7, jbcs-httpd24-curl 7.78.0-2.jbcs.el7, jbcs-httpd24-httpd 2.4.37-78.jbcs.el7, jbcs-httpd24-mod_md 2.0.8-40.jbcs.el7, jbcs-httpd24-libcurl 7.78.0-2.jbcs.el7, jbcs-httpd24-openssl 1.1.1g-8.jbcs.el7, +26 more Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-apr 1.6.3-107.el8jbcs, jbcs-httpd24-curl 7.78.0-2.el8jbcs, jbcs-httpd24-httpd 2.4.37-78.el8jbcs, jbcs-httpd24-mod_md 2.0.8-40.el8jbcs, jbcs-httpd24-libcurl 7.78.0-2.el8jbcs, jbcs-httpd24-openssl 1.1.1g-8.el8jbcs, +26 more
    fixed: vendor fix “Manually add LocationMatch directive to deny any possible problem requests in the JBCS httpd configuration. For example: ~~~ <LocationMatch ".*\.\.;.*"> Require all denied </LocationMatch> ~~~” RHSA-2021:4614
  • Red Hat Enterprise Linux 6 httpd, mod_ssl, httpd-tools, httpd-manual Red Hat Enterprise Linux 7 httpd, mod_ssl, mod_ldap, httpd-tools, mod_session, httpd-manual, +1 more Red Hat Enterprise Linux 8 httpd, mod_md, mod_ssl, mod_ldap, mod_http2, httpd-tools, +5 more Red Hat Enterprise Linux 9 httpd, mod_lua, mod_ssl, mod_ldap, httpd-core, httpd-tools, +4 more Red Hat Software Collections httpd24-httpd, httpd24-mod_md, httpd24-mod_ssl, httpd24-mod_ldap, httpd24-httpd-tools, httpd24-mod_session, +2 more
    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

0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected products

  • n/a Red Hat JBCS HTTP Server

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

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.