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Fencer Vulns
high 7.5

CVE-2026-34483 json

Apache Tomcat: Incomplete escaping of JSON access logs

published 2026-04-09 7 mo ago modified 2026-10-26 13 d ago also BIT-tomcat-2026-34483 , EUVD-2026-21053 , GHSA-rv64-5gf8-9qq8

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.40 through 9.0.116.

Users are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117 , which fix the issue.

Patch / fix

  • maven org.apache.tomcat:tomcat-catalina 9.0.116, 10.1.54, 11.0.21
  • maven org.apache.tomcat:tomcat 9.0.116, 10.1.54, 11.0.21
  • maven org.apache.tomcat.embed:tomcat-embed-core 9.0.116, 10.1.54, 11.0.21
  • bitnami tomcat 9.0.117, 10.1.54, 11.0.21
  • apache tomcat 9.0.117, 10.1.54, 11.0.21
  • org.apache.tomcat tomcat 9.0.117, 10.1.54, 11.0.21
  • apache tomcat-catalina 9.0.117, 10.1.54, 11.0.21
  • org.apache.tomcat tomcat-catalina 9.0.117, 10.1.54, 11.0.21
  • apache tomcat-embed-core 9.0.117, 10.1.54, 11.0.21
  • org.apache.tomcat.embed tomcat-embed-core 9.0.117, 10.1.54, 11.0.21
  • tomcat9 Debian 14, Debian 13, Debian 12 9.0.70-2
  • tomcat10 Debian 12 10.1.55-1~deb12u1
  • tomcat10 Debian 13 10.1.55-1~deb13u1
  • tomcat10 Debian 14 10.1.54-1
  • tomcat11 Debian 13 11.0.22-1~deb13u1
  • tomcat11 Debian 14 11.0.21-1

debian advisories DEBIAN-CVE-2026-34483

  • tomcat RHEL 8 1:9.0.120-1.el8_10
  • tomcat-lib RHEL 8 1:9.0.120-1.el8_10
  • tomcat-webapps RHEL 8 1:9.0.120-1.el8_10
  • tomcat-el-3.0-api RHEL 8 1:9.0.120-1.el8_10
  • tomcat-docs-webapp RHEL 8 1:9.0.120-1.el8_10
  • tomcat-jsp-2.3-api RHEL 8 1:9.0.120-1.el8_10
  • tomcat-admin-webapps RHEL 8 1:9.0.120-1.el8_10
  • tomcat-servlet-4.0-api RHEL 8 1:9.0.120-1.el8_10

red hat advisories RHSA-2026:68680RHSA-2026:68679RHSA-2026:68677RHSA-2026:68678RHSA-2026:68659RHSA-2026:67163

  • tomcat SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 9.0.117-150200.105.1
  • tomcat10 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES 15 SP6-LTSS +4 more 10.1.54-150200.5.64.1
  • tomcat11 SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Web and Scripting 15 SP7 11.0.21-150600.13.18.1
  • tomcat SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 9.0.117-3.163.2

suse advisories SUSE-SU-2026:1604-1SUSE-SU-2026:1603-1SUSE-SU-2026:1572-1SUSE-SU-2026:1558-1

  • tomcat openSUSE Leap 16.0 9.0.117-160000.1.1
  • tomcat10 openSUSE Leap 16.0 10.1.54-160000.1.1
  • tomcat11 openSUSE Leap 16.0 11.0.21-160000.1.1
  • tomcat openSUSE Tumbleweed 9.0.117-1.1
  • tomcat10 openSUSE Tumbleweed 10.1.54-1.1
  • tomcat11 openSUSE Tumbleweed 11.0.21-1.1

opensuse advisories openSUSE-SU-2026:20611-1openSUSE-SU-2026:20612-1openSUSE-SU-2026:20595-1openSUSE-SU-2026:10547-1openSUSE-SU-2026:10548-1openSUSE-SU-2026:10549-1

  • tomcat AlmaLinux 8 1:9.0.120-1.el8_10
  • tomcat-lib AlmaLinux 8 1:9.0.120-1.el8_10
  • tomcat-webapps AlmaLinux 8 1:9.0.120-1.el8_10
  • tomcat-el-3.0-api AlmaLinux 8 1:9.0.120-1.el8_10
  • tomcat-docs-webapp AlmaLinux 8 1:9.0.120-1.el8_10
  • tomcat-jsp-2.3-api AlmaLinux 8 1:9.0.120-1.el8_10
  • tomcat-admin-webapps AlmaLinux 8 1:9.0.120-1.el8_10
  • tomcat-servlet-4.0-api AlmaLinux 8 1:9.0.120-1.el8_10

almalinux advisories ALSA-2026:68677ALSA-2026:36790ALSA-2026:26323ALSA-2026:25341

  • tomcat9 Rocky Linux 10 1:9.0.117-1.el10_2

rocky linux advisories RLSA-2026:25341

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-2026-34483 updated cvss 5.4

Apache Tomcat: Apache Tomcat: Information disclosure due to improper encoding in JsonAccessLogValve

  • Red Hat Enterprise Linux 6 tomcat6, tomcat6-lib, tomcat6-log4j, tomcat6-javadoc, tomcat6-webapps, tomcat6-el-2.1-api, +4 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 tomcat, tomcat-lib, tomcat-jsvc, tomcat-javadoc, tomcat-webapps, tomcat-el-2.2-api, +4 more Red Hat Enterprise Linux 8 pki-servlet-engine, pki-servlet-4.0-api Red Hat Enterprise Linux 9 pki-servlet-engine, pki-servlet-4.0-api Red Hat Enterprise Linux 10 tomcat
    affected: workaround, no fix available “Fix deferred”
  • Red Hat JBoss Web Server 5 tomcat
    under investigation
  • Red Hat Enterprise Linux AppStream (v. 8) tomcat 9.0.120-1.el8_10, tomcat-lib 9.0.120-1.el8_10, tomcat-webapps 9.0.120-1.el8_10, tomcat-el-3.0-api 9.0.120-1.el8_10, tomcat-docs-webapp 9.0.120-1.el8_10, tomcat-jsp-2.3-api 9.0.120-1.el8_10, +2 more
    fixed: vendor fix RHSA-2026:68677
  • Red Hat Enterprise Linux AppStream (v. 9) tomcat 9.0.117-1.el9_8, tomcat-lib 9.0.117-1.el9_8, tomcat-webapps 9.0.117-1.el9_8, tomcat-el-3.0-api 9.0.117-1.el9_8, tomcat-docs-webapp 9.0.117-1.el9_8, tomcat-jsp-2.3-api 9.0.117-1.el9_8, +2 more
    fixed: vendor fix RHSA-2026:26323
  • Red Hat Enterprise Linux AppStream (v. 10) tomcat9 9.0.117-1.el10_2, tomcat9-lib 9.0.117-1.el10_2, tomcat9-webapps 9.0.117-1.el10_2, tomcat9-el-3.0-api 9.0.117-1.el10_2, tomcat9-docs-webapp 9.0.117-1.el10_2, tomcat9-jsp-2.3-api 9.0.117-1.el10_2, +2 more
    fixed: vendor fix RHSA-2026:25341
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) tomcat 9.0.120-1.el8_8, tomcat-lib 9.0.120-1.el8_8, tomcat-webapps 9.0.120-1.el8_8, tomcat-el-3.0-api 9.0.120-1.el8_8, tomcat-docs-webapp 9.0.120-1.el8_8, tomcat-jsp-2.3-api 9.0.120-1.el8_8, +2 more
    fixed: vendor fix RHSA-2026:68680
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) tomcat 9.0.120-1.el9_2, tomcat-lib 9.0.120-1.el9_2, tomcat-webapps 9.0.120-1.el9_2, tomcat-el-3.0-api 9.0.120-1.el9_2, tomcat-docs-webapp 9.0.120-1.el9_2, tomcat-jsp-2.3-api 9.0.120-1.el9_2, +2 more
    fixed: vendor fix RHSA-2026:68678
show 6 more
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) tomcat 9.0.120-1.el9_4, tomcat-lib 9.0.120-1.el9_4, tomcat-webapps 9.0.120-1.el9_4, tomcat-el-3.0-api 9.0.120-1.el9_4, tomcat-docs-webapp 9.0.120-1.el9_4, tomcat-jsp-2.3-api 9.0.120-1.el9_4, +2 more
    fixed: vendor fix RHSA-2026:68679
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) tomcat9 9.0.120-1.el10_0, tomcat9-lib 9.0.120-1.el10_0, tomcat9-webapps 9.0.120-1.el10_0, tomcat9-el-3.0-api 9.0.120-1.el10_0, tomcat9-docs-webapp 9.0.120-1.el10_0, tomcat9-jsp-2.3-api 9.0.120-1.el10_0, +2 more
    fixed: vendor fix RHSA-2026:67163
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) tomcat 9.0.120-1.el9_6, tomcat-lib 9.0.120-1.el9_6, tomcat-webapps 9.0.120-1.el9_6, tomcat-el-3.0-api 9.0.120-1.el9_6, tomcat-docs-webapp 9.0.120-1.el9_6, tomcat-jsp-2.3-api 9.0.120-1.el9_6, +2 more
    fixed: vendor fix RHSA-2026:68659
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) tomcat 9.0.120-1.el8_8, tomcat-lib 9.0.120-1.el8_8, tomcat-webapps 9.0.120-1.el8_8, tomcat-el-3.0-api 9.0.120-1.el8_8, tomcat-docs-webapp 9.0.120-1.el8_8, tomcat-jsp-2.3-api 9.0.120-1.el8_8, +2 more
    fixed: vendor fix RHSA-2026:68680
  • Red Hat JBoss Web Server 6.2 on RHEL 8 jws6-tomcat 10.1.49-13.redhat_00011.1.el8jws, jws6-tomcat-lib 10.1.49-13.redhat_00011.1.el8jws, jws6-tomcat-javadoc 10.1.49-13.redhat_00011.1.el8jws, jws6-tomcat-selinux 10.1.49-13.redhat_00011.1.el8jws, jws6-tomcat-webapps 10.1.49-13.redhat_00011.1.el8jws, jws6-tomcat-el-5.0-api 10.1.49-13.redhat_00011.1.el8jws, +4 more Red Hat JBoss Web Server 6.2 on RHEL 9 jws6-tomcat 10.1.49-13.redhat_00011.1.el9jws, jws6-tomcat-lib 10.1.49-13.redhat_00011.1.el9jws, jws6-tomcat-javadoc 10.1.49-13.redhat_00011.1.el9jws, jws6-tomcat-selinux 10.1.49-13.redhat_00011.1.el9jws, jws6-tomcat-webapps 10.1.49-13.redhat_00011.1.el9jws, jws6-tomcat-el-5.0-api 10.1.49-13.redhat_00011.1.el9jws, +4 more Red Hat JBoss Web Server 6.2 on RHEL 10 jws6-tomcat 10.1.49-13.redhat_00011.1.el10jws, jws6-tomcat-lib 10.1.49-13.redhat_00011.1.el10jws, jws6-tomcat-javadoc 10.1.49-13.redhat_00011.1.el10jws, jws6-tomcat-selinux 10.1.49-13.redhat_00011.1.el10jws, jws6-tomcat-webapps 10.1.49-13.redhat_00011.1.el10jws, jws6-tomcat-el-5.0-api 10.1.49-13.redhat_00011.1.el10jws, +4 more
    fixed: vendor fix RHSA-2026:20405
  • Red Hat JBoss Web Server 6.2.3
    fixed: vendor fix RHSA-2026:20406

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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
maven org.apache.tomcat:tomcat-catalina
>=9.0.40, <9.0.116
>=10.1.0-M1, <10.1.54
>=11.0.0-M1, <11.0.21
9.0.116
10.1.54
11.0.21
maven org.apache.tomcat:tomcat
>=9.0.40, <9.0.116
>=10.1.0-M1, <10.1.54
>=11.0.0-M1, <11.0.21
9.0.116
10.1.54
11.0.21
maven org.apache.tomcat.embed:tomcat-embed-core
>=9.0.40, <9.0.116
>=10.1.0-M1, <10.1.54
>=11.0.0-M1, <11.0.21
9.0.116
10.1.54
11.0.21
bitnami tomcat
>=9.0.40, <9.0.117
>=10.0.0, <10.1.54
>=11.0.0, <11.0.21
9.0.117
10.1.54
11.0.21

Affected products

  • Apache Software Foundation Apache Tomcat

Classification

Weakness
  • CWE-116 Improper Encoding or Escaping of Output

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.