CVE-2018-20843
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).
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (7.11%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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).
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 7.11% probability · 94th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-611
- Affected
- libexpat project/libexpat · canonical/ubuntu linux · debian/debian linux · fedoraproject/fedora · opensuse/leap · oracle/hospitality res 3700 · oracle/http server · oracle/outside in technology · tenable/nessus
- Source
- cve@mitre.org
EPSS 7.1% since 27 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.htmlMailing List, Third Party Advisory
- https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226Issue Tracking, Third Party Advisory
- https://github.com/libexpat/libexpat/blob/R_2_2_7/expat/ChangesRelease Notes, Third Party Advisory
- https://github.com/libexpat/libexpat/issues/186Issue Tracking, Patch, Third Party Advisory
- https://github.com/libexpat/libexpat/pull/262Exploit, Patch, Third Party Advisory
- https://github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/06/msg00028.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEJJSQSG3KSUQY4FPVHZ7ZTT7FORMFVD/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IDAUGEB3TUP6NEKJDBUBZX7N5OAUOOOK/
- https://seclists.org/bugtraq/2019/Jun/39Mailing List, Third Party Advisory
- https://security.gentoo.org/glsa/201911-08Third Party Advisory
- https://security.netapp.com/advisory/ntap-20190703-0001/Third Party Advisory
- https://support.f5.com/csp/article/K51011533Third Party Advisory
- https://usn.ubuntu.com/4040-1/Third Party Advisory
- https://usn.ubuntu.com/4040-2/Third Party Advisory
- https://www.debian.org/security/2019/dsa-4472Third Party Advisory
- https://www.oracle.com/security-alerts/cpuApr2021.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuapr2020.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2020.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
- https://www.tenable.com/security/tns-2021-11Third Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.htmlMailing List, Third Party Advisory
- https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226Issue Tracking, Third Party Advisory
- https://github.com/libexpat/libexpat/blob/R_2_2_7/expat/ChangesRelease Notes, Third Party Advisory
- https://github.com/libexpat/libexpat/issues/186Issue Tracking, Patch, Third Party Advisory
- https://github.com/libexpat/libexpat/pull/262Exploit, Patch, Third Party Advisory
- https://github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/06/msg00028.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEJJSQSG3KSUQY4FPVHZ7ZTT7FORMFVD/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IDAUGEB3TUP6NEKJDBUBZX7N5OAUOOOK/
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.