expat: large number of colons in input makes parser consume high amount of resources, leading to DoS
Published Jun 24, 2019
7.5
HIGHCVSS 3.1
EPSS 7.11%
Description
In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).
Affected products
No data.
Configuration 1
- < 2.2.7
Configuration 2
- 12.04
- 14.04
- 16.04
- 18.04
- 18.10
- 19.04
Configuration 3
- 8.0
- 9.0
Configuration 4
- 29
- 30
Configuration 6
- ≥ 5.7 · ≤ 5.7.6
- 12.1.3.0
- 12.2.1.4.0
- 8.5.4
- 8.5.5
No data.
JBoss Core Services on RHEL 6
jbcs-httpd24-curl-0:7.64.1-36.jbcs.el6
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 6
jbcs-httpd24-httpd-0:2.4.37-57.jbcs.el6
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 6
jbcs-httpd24-mod_cluster-native-0:1.3.14-4.Final_redhat_2.jbcs.el6
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 6
jbcs-httpd24-mod_http2-0:1.15.7-3.jbcs.el6
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 6
jbcs-httpd24-mod_jk-0:1.2.48-4.redhat_1.jbcs.el6
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 6
jbcs-httpd24-mod_md-1:2.0.8-24.jbcs.el6
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 6
jbcs-httpd24-mod_security-0:2.9.2-51.GA.jbcs.el6
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 6
jbcs-httpd24-nghttp2-0:1.39.2-25.jbcs.el6
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 7
jbcs-httpd24-curl-0:7.64.1-36.jbcs.el7
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 7
jbcs-httpd24-httpd-0:2.4.37-57.jbcs.el7
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 7
jbcs-httpd24-mod_cluster-native-0:1.3.14-4.Final_redhat_2.jbcs.el7
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 7
jbcs-httpd24-mod_http2-0:1.15.7-3.jbcs.el7
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 7
jbcs-httpd24-mod_jk-0:1.2.48-4.redhat_1.jbcs.el7
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 7
jbcs-httpd24-mod_md-1:2.0.8-24.jbcs.el7
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 7
jbcs-httpd24-mod_security-0:2.9.2-51.GA.jbcs.el7
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 7
jbcs-httpd24-nghttp2-0:1.39.2-25.jbcs.el7
Fixed · RHSA-2020:2644
JBoss Core Services on RHEL 7
jbcs-httpd24-openssl-pkcs11-0:0.4.10-7.jbcs.el7
Fixed · RHSA-2020:2644
Red Hat Enterprise Linux 7
expat-0:2.1.0-12.el7
Fixed · RHSA-2020:3952
Red Hat Enterprise Linux 8
expat-0:2.2.5-4.el8
Fixed · RHSA-2020:4484
Red Hat Enterprise Linux 8
mingw-expat-0:2.2.4-5.el8
Fixed · RHSA-2020:4846
Red Hat Enterprise Linux 8.2 Advanced Update Support
expat-0:2.2.10-1.el8_2
Fixed · RHSA-2025:22871
Red Hat JBoss Core Services
expat
Fixed · RHSA-2020:2646
Red Hat OpenShift Do
openshiftdo/odo-init-image-rhel7:1.1.3-2
Fixed · RHSA-2021:0949
Red Hat Enterprise Linux 5
expat
Out of support scope
Red Hat Enterprise Linux 5
firefox
Not affected
Red Hat Enterprise Linux 5
thunderbird
Not affected
Red Hat Enterprise Linux 5
xmlrpc-c
Out of support scope
Red Hat Enterprise Linux 5
xulrunner
Not affected
Red Hat Enterprise Linux 6
compat-expat1
Out of support scope
Red Hat Enterprise Linux 6
expat
Out of support scope
Red Hat Enterprise Linux 6
firefox
Not affected
Red Hat Enterprise Linux 6
thunderbird
Not affected
Red Hat Enterprise Linux 6
xulrunner
Not affected
Red Hat Enterprise Linux 7
firefox
Not affected
Red Hat Enterprise Linux 7
thunderbird
Not affected
Red Hat Enterprise Linux 7
xulrunner
Not affected
Red Hat JBoss Enterprise Application Platform 6
httpd
Out of support scope
Red Hat JBoss Enterprise Web Server 2
httpd
Out of support scope
| Product | Package | State | Advisory |
|---|---|---|---|
| JBoss Core Services on RHEL 6 | jbcs-httpd24-curl-0:7.64.1-36.jbcs.el6 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 6 | jbcs-httpd24-httpd-0:2.4.37-57.jbcs.el6 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 6 | jbcs-httpd24-mod_cluster-native-0:1.3.14-4.Final_redhat_2.jbcs.el6 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 6 | jbcs-httpd24-mod_http2-0:1.15.7-3.jbcs.el6 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 6 | jbcs-httpd24-mod_jk-0:1.2.48-4.redhat_1.jbcs.el6 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 6 | jbcs-httpd24-mod_md-1:2.0.8-24.jbcs.el6 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 6 | jbcs-httpd24-mod_security-0:2.9.2-51.GA.jbcs.el6 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 6 | jbcs-httpd24-nghttp2-0:1.39.2-25.jbcs.el6 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-curl-0:7.64.1-36.jbcs.el7 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-httpd-0:2.4.37-57.jbcs.el7 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-mod_cluster-native-0:1.3.14-4.Final_redhat_2.jbcs.el7 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-mod_http2-0:1.15.7-3.jbcs.el7 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-mod_jk-0:1.2.48-4.redhat_1.jbcs.el7 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-mod_md-1:2.0.8-24.jbcs.el7 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-mod_security-0:2.9.2-51.GA.jbcs.el7 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-nghttp2-0:1.39.2-25.jbcs.el7 | Fixed | RHSA-2020:2644 |
| JBoss Core Services on RHEL 7 | jbcs-httpd24-openssl-pkcs11-0:0.4.10-7.jbcs.el7 | Fixed | RHSA-2020:2644 |
| Red Hat Enterprise Linux 7 | expat-0:2.1.0-12.el7 | Fixed | RHSA-2020:3952 |
| Red Hat Enterprise Linux 8 | expat-0:2.2.5-4.el8 | Fixed | RHSA-2020:4484 |
| Red Hat Enterprise Linux 8 | mingw-expat-0:2.2.4-5.el8 | Fixed | RHSA-2020:4846 |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | expat-0:2.2.10-1.el8_2 | Fixed | RHSA-2025:22871 |
| Red Hat JBoss Core Services | expat | Fixed | RHSA-2020:2646 |
| Red Hat OpenShift Do | openshiftdo/odo-init-image-rhel7:1.1.3-2 | Fixed | RHSA-2021:0949 |
| Red Hat Enterprise Linux 5 | expat | Out of support scope | n/a |
| Red Hat Enterprise Linux 5 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 5 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 5 | xmlrpc-c | Out of support scope | n/a |
| Red Hat Enterprise Linux 5 | xulrunner | Not affected | n/a |
| Red Hat Enterprise Linux 6 | compat-expat1 | Out of support scope | n/a |
| Red Hat Enterprise Linux 6 | expat | Out of support scope | n/a |
| Red Hat Enterprise Linux 6 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 6 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 6 | xulrunner | Not affected | n/a |
| Red Hat Enterprise Linux 7 | firefox | Not affected | n/a |
| Red Hat Enterprise Linux 7 | thunderbird | Not affected | n/a |
| Red Hat Enterprise Linux 7 | xulrunner | Not affected | n/a |
| Red Hat JBoss Enterprise Application Platform 6 | httpd | Out of support scope | n/a |
| Red Hat JBoss Enterprise Web Server 2 | httpd | Out of support scope | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
When processing a specially crafted XML file, expat may use more memory than ultimately necessary, which can also lead to increased CPU usage and longer processing times. Depending on available system resources and configuration, this may also lead to the application triggering the Out-Of-Memory-Killer, causing the application to be terminated.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
No CVSS v3.0 score for this CVE.
AV:N/AC:L/Au:N/C:N/I:N/A:C
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
NoneAutomatable
YesTechnical Impact
PartialDecision
n/aAssessed May 30, 2025 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (57 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 7.11% (0.07107) | 94.05th | v5 (v2026.06.15) |
| Jun 15, 2026 | 7.11% (0.07107) | 93.40th | v5 (v2026.06.15) |
| Mar 4, 2026 | 5.69% (0.05686) | 90.23th | v4 (v2025.03.14) |
| Mar 1, 2026 | 0.77% (0.00766) | 73.25th | v4 (v2025.03.14) |
| Feb 4, 2026 | 5.83% (0.05826) | 90.30th | v4 (v2025.03.14) |
| Feb 1, 2026 | 0.79% (0.00786) | 73.47th | v4 (v2025.03.14) |
| Jan 4, 2026 | 5.83% (0.05826) | 90.23th | v4 (v2025.03.14) |
| Jan 1, 2026 | 0.79% (0.00786) | 73.40th | v4 (v2025.03.14) |
| Dec 30, 2025 | 5.83% (0.05826) | 90.22th | v4 (v2025.03.14) |
| Dec 18, 2025 | 4.53% (0.04530) | 88.77th | v4 (v2025.03.14) |
| Dec 4, 2025 | 5.98% (0.05976) | 90.30th | v4 (v2025.03.14) |
| Dec 1, 2025 | 0.81% (0.00808) | 73.56th | v4 (v2025.03.14) |
| Nov 21, 2025 | 5.83% (0.05826) | 90.13th | v4 (v2025.03.14) |
| Nov 18, 2025 | 36.68% (0.36677) | 96.94th | v4 (v2025.03.14) |
| Nov 4, 2025 | 5.82% (0.05817) | 90.10th | v4 (v2025.03.14) |
| Nov 1, 2025 | 0.78% (0.00785) | 73.16th | v4 (v2025.03.14) |
| Oct 4, 2025 | 5.82% (0.05817) | 90.13th | v4 (v2025.03.14) |
| Oct 1, 2025 | 0.78% (0.00785) | 73.07th | v4 (v2025.03.14) |
| Sep 4, 2025 | 5.82% (0.05817) | 90.20th | v4 (v2025.03.14) |
| Sep 1, 2025 | 0.77% (0.00766) | 72.63th | v4 (v2025.03.14) |
| Aug 5, 2025 | 5.69% (0.05686) | 90.04th | v4 (v2025.03.14) |
| Aug 1, 2025 | 0.77% (0.00766) | 72.60th | v4 (v2025.03.14) |
| Jul 5, 2025 | 5.82% (0.05817) | 90.09th | v4 (v2025.03.14) |
| Jul 1, 2025 | 0.78% (0.00785) | 72.88th | v4 (v2025.03.14) |
| Jun 4, 2025 | 5.82% (0.05817) | 90.05th | v4 (v2025.03.14) |
| Jun 1, 2025 | 0.78% (0.00785) | 72.73th | v4 (v2025.03.14) |
| May 5, 2025 | 5.82% (0.05817) | 89.99th | v4 (v2025.03.14) |
| May 1, 2025 | 0.78% (0.00785) | 72.59th | v4 (v2025.03.14) |
| Apr 20, 2025 | 5.83% (0.05833) | 90.01th | v4 (v2025.03.14) |
| Apr 19, 2025 | 0.79% (0.00787) | 72.57th | v4 (v2025.03.14) |
| Apr 15, 2025 | 5.69% (0.05686) | 89.84th | v4 (v2025.03.14) |
| Apr 13, 2025 | 0.78% (0.00775) | 71.43th | v4 (v2025.03.14) |
| Apr 11, 2025 | 5.69% (0.05686) | 89.53th | v4 (v2025.03.14) |
| Apr 10, 2025 | 1.40% (0.01403) | 78.81th | v4 (v2025.03.14) |
| Mar 30, 2025 | 9.88% (0.09880) | 92.25th | v4 (v2025.03.14) |
| Mar 29, 2025 | 11.89% (0.11893) | 89.54th | v4 (v2025.03.14) |
| Mar 21, 2025 | 9.88% (0.09880) | 92.35th | v4 (v2025.03.14) |
| Mar 20, 2025 | 1.40% (0.01403) | 78.77th | v4 (v2025.03.14) |
| Mar 17, 2025 | 9.88% (0.09880) | 92.43th | v4 (v2025.03.14) |
| Dec 17, 2024 | 70.35% (0.70350) | 98.21th | v3 (v2023.03.01) |
| Nov 14, 2024 | 50.66% (0.50663) | 97.64th | v3 (v2023.03.01) |
| Jun 17, 2024 | 58.20% (0.58200) | 97.74th | v3 (v2023.03.01) |
| Nov 8, 2023 | 60.91% (0.60910) | 97.46th | v3 (v2023.03.01) |
| Oct 18, 2023 | 89.87% (0.89868) | 98.42th | v3 (v2023.03.01) |
| Mar 7, 2023 | 91.48% (0.91481) | 98.28th | v3 (v2023.03.01) |
| Mar 6, 2023 | 2.69% (0.02686) | 82.85th | v2 (v2022.01.01) |
| Apr 1, 2022 | 2.69% (0.02686) | 81.17th | v2 (v2022.01.01) |
| Feb 4, 2022 | 2.69% (0.02686) | 62.66th | v2 (v2022.01.01) |
| Feb 3, 2022 | 4.47% (0.04466) | 74.74th | v1 |
| Jan 6, 2022 | 4.47% (0.04466) | 74.53th | v1 |
| Oct 21, 2021 | 4.47% (0.04466) | 84.01th | v1 |
| Sep 1, 2021 | 4.27% (0.04270) | 83.53th | v1 |
| Jun 24, 2021 | 4.27% (0.04270) | 0.00th | v1 |
| Jun 19, 2021 | 16.68% (0.16676) | 0.00th | v1 |
| Jun 16, 2021 | 4.27% (0.04270) | 0.00th | v1 |
| Jun 15, 2021 | 4.07% (0.04074) | 0.00th | v1 |
| Apr 14, 2021 | 3.88% (0.03876) | 0.00th | v1 |
References (26)
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.html vendor-advisoryx_refsource_SUSEMailing ListThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2018-20843 Vendor Advisory
- https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226 x_refsource_MISCIssue TrackingThird Party Advisory
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=931031
- https://bugzilla.redhat.com/show_bug.cgi?id=1723723 Issue Tracking
- https://github.com/libexpat/libexpat/blob/R_2_2_7/expat/Changes x_refsource_MISCRelease NotesThird Party Advisory
- https://github.com/libexpat/libexpat/issues/186 x_refsource_MISCIssue TrackingPatchThird Party Advisory
- https://github.com/libexpat/libexpat/pull/262 x_refsource_MISCExploitPatchThird Party Advisory
- https://github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6 x_refsource_MISCPatchThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/06/msg00028.html mailing-listx_refsource_MLISTMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEJJSQSG3KSUQY4FPVHZ7ZTT7FORMFVD/ vendor-advisoryx_refsource_FEDORA
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IDAUGEB3TUP6NEKJDBUBZX7N5OAUOOOK/ vendor-advisoryx_refsource_FEDORA
- https://nvd.nist.gov/vuln/detail/CVE-2018-20843
- https://seclists.org/bugtraq/2019/Jun/39 mailing-listx_refsource_BUGTRAQMailing ListThird Party Advisory
- https://security.gentoo.org/glsa/201911-08 vendor-advisoryx_refsource_GENTOOThird Party Advisory
- https://security.netapp.com/advisory/ntap-20190703-0001/ x_refsource_CONFIRMThird Party Advisory
- https://support.f5.com/csp/article/K51011533 x_refsource_CONFIRMThird Party Advisory
- https://usn.ubuntu.com/4040-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://usn.ubuntu.com/4040-2/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2018-20843
- https://www.debian.org/security/2019/dsa-4472 vendor-advisoryx_refsource_DEBIANThird Party Advisory
- https://www.oracle.com/security-alerts/cpuApr2021.html x_refsource_MISCPatchThird Party Advisory
- https://www.oracle.com/security-alerts/cpuapr2020.html x_refsource_MISCPatchThird Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2020.html x_refsource_MISCPatchThird Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.html x_refsource_MISCPatchThird Party Advisory
- https://www.tenable.com/security/tns-2021-11 x_refsource_CONFIRMThird Party Advisory
Change history (0)
No recorded changes yet.