CVE-2026-45186
published 2026-05-10CVE-2026-45186: In libexpat before 2.8.1, the computational complexity of attribute name collision checks allows a denial of service via moderately sized crafted XML input.
PriorityP338high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
0.44%
36.2th percentile
In libexpat before 2.8.1, the computational complexity of attribute name collision checks allows a denial of service via moderately sized crafted XML input.
Affected
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | expat | — | — |
| libexpat_project | libexpat | < 2.8.1 | 2.8.1 |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vendor_redhat7.5HIGH
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Red Hat
libexpat: denial of service via crafted XML input
vendor_redhat·2026-05-10·CVSS 7.5
CVE-2026-45186 [HIGH] CWE-407 libexpat: denial of service via crafted XML input
libexpat: denial of service via crafted XML input
A flaw was found in libexpat. When processing a specially crafted XML input containing a specific pattern of attributes, the parsing time increases quadratically due to checks for attribute name collisions. This consumes excessive CPU resources and eventually results in a denial of service.
Statement: To exploit this issue, an attacker needs to be able to process a specially crafted XML file or input with an application linked to the libexpat library. Also, the only security impact of this flaw is a high consumption of CPU resources that can eventually cause a denial of service. Due to this reason, this vulnerability has been rated with an important severity.
Mitigation: To mitigate this vulnerability, restrict the maximum size of incomi
GHSA
GHSA-r396-2q2c-pjhr: In libexpat before 2
ghsa_unreviewed·2026-05-10
CVE-2026-45186 [LOW] CWE-407 GHSA-r396-2q2c-pjhr: In libexpat before 2
In libexpat before 2.8.1, the computational complexity of attribute name collision checks allows a denial of service via moderately sized crafted XML input.
VulDB
libexpat up to 2.8.0 XML algorithmic complexity (EUVD-2026-28985 / Nessus ID 313709)
vuldb·2026-05-10·CVSS 2.9
CVE-2026-45186 [LOW] libexpat up to 2.8.0 XML algorithmic complexity (EUVD-2026-28985 / Nessus ID 313709)
A vulnerability classified as problematic was found in libexpat up to 2.8.0. Impacted is an unknown function of the component XML Handler. Executing a manipulation can lead to inefficient algorithmic complexity.
This vulnerability appears as CVE-2026-45186. The attack requires local access. There is no available exploit.
Upgrading the affected component is advised.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-45186 expat: denial of service via crafted XML input [fedora-all]
bugzilla·2026-05-19·CVSS 7.5
CVE-2026-45186 [HIGH] CVE-2026-45186 expat: denial of service via crafted XML input [fedora-all]
CVE-2026-45186 expat: denial of service via crafted XML input [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-45186 mingw-expat: denial of service via crafted XML input [fedora-all]
bugzilla·2026-05-19·CVSS 7.5
CVE-2026-45186 [HIGH] CVE-2026-45186 mingw-expat: denial of service via crafted XML input [fedora-all]
CVE-2026-45186 mingw-expat: denial of service via crafted XML input [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-45186 libexpat: denial of service via crafted XML input
bugzilla·2026-05-10·CVSS 7.5
CVE-2026-45186 [HIGH] CVE-2026-45186 libexpat: denial of service via crafted XML input
CVE-2026-45186 libexpat: denial of service via crafted XML input
In libexpat before 2.8.1, the computational complexity of attribute name collision checks allows a denial of service via moderately sized crafted XML input.
Rapid7
Patch Tuesday - May 2026
blogs_rapid7·2026-05-13·CVSS 10.0
CVE-2026-41089 [CRITICAL] Patch Tuesday - May 2026
Microsoft is publishing 137 vulnerabilities on May 2026 Patch Tuesday . Microsoft is not aware of exploitation in the wild or public disclosure for any of these vulnerabilities. So far this month, Microsoft has provided patches to address 133 browser vulnerabilities, which are not included in the Patch Tuesday count above.
## Windows Netlogon: critical RCE
Anyone responsible for securing a domain controller should prioritize remediation of CVE-2026-41089 , which is a critical stack-based buffer overflow in Windows Netlogon with a CVSS v3 base score of 9.8. Exploitation leads to execution in the context of the Netlogon service, so that’s SYSTEM privileges on the domain controller. For most pentesters, that’s the point at which the customer report more or less writes itself. No privileges
https://github.com/libexpat/libexpat/pull/1216http://www.openwall.com/lists/oss-security/2026/05/11/16https://access.redhat.com/errata/RHSA-2026:22715https://access.redhat.com/errata/RHSA-2026:22721https://access.redhat.com/errata/RHSA-2026:23230https://access.redhat.com/errata/RHSA-2026:26319https://access.redhat.com/errata/RHSA-2026:27201https://access.redhat.com/errata/RHSA-2026:29197https://access.redhat.com/security/cve/CVE-2026-45186https://bugzilla.redhat.com/show_bug.cgi?id=2468575https://cert-portal.siemens.com/productcert/html/ssa-082556.htmlhttps://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-45186.json
2026-05-10
Published