Home/CVE/In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XM
CVE

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 XM

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).

HIGH · CVSS 7.5 EPSS 0.05584
Act now
  • EPSS percentile: top 10% of all CVEs by exploitation likelihood
  • Public exploit or PoC is available
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-611Improper Restriction of XML External Entity Reference
CWE-611Improper Restriction of XML External Entity Reference
▤

Affected Products & Versions

9
libexpat project libexpat< 2.2.7
canonical ubuntu linuxall versions
debian linuxall versions
fedoraproject fedoraall versions
opensuse leapall versions
oracle hospitality res 3700>= 5.7 and <= 5.7.6
oracle http serverall versions
oracle outside in technologyall versions
⚠

Public Exploits & PoCs

1
pocgithub.com · pull/262github.com
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD24 Jun 2019 · 05:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

19
rhsaRHSA-2025:22871Important
usnUSN-7199-1
suse-csafopenSUSE-SU-2024:10748-1
siemens-csafSSA-398330
usnUSN-5455-1
🔗

References & Sources

20
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.htmlMailing ListThird Party Advisory
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226Issue TrackingThird Party Advisory
https://github.com/libexpat/libexpat/blob/R_2_2_7/expat/ChangesRelease NotesThird Party Advisory
https://github.com/libexpat/libexpat/issues/186Issue TrackingPatchThird Party Advisory
https://github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6PatchThird Party Advisory
https://lists.debian.org/debian-lts-announce/2019/06/msg00028.htmlMailing ListThird Party Advisory
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