CVE search · CVE-2026-66046
CVE-2026-66046
high 8.7
Expat through 2.8.3 contains a denial of service vulnerability caused by quadratic algorithmic complexity in the storeAtts() function in xmlparse.c, where processing N specified attributes with non-normalized values triggers an O(N^2) linear scan of elementType->defaultAtts to determine CDATA status. A remote unauthenticated attacker can supply a single well-formed XML document of a few megabytes to an application parsing untrusted XML to cause excessive CPU consumption, resulting in denial of service without requiring authentication, external entity resolution, or non-default parser options.
Details
- Status
- Modified
- Published
- Last changed
- Source
- disclosure@vulncheck.com
- Weakness
- CWE-407
Severity
| Version | Score | Vector | Source |
|---|---|---|---|
| CVSS 4.0 | high 8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
disclosure@vulncheck.comSecondary |
| CVSS 3.1 | high 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
disclosure@vulncheck.comSecondary |
Affected products
Vendor and product from the NVD’s CPE applicability statements. Versions and conditions are on the NVD’s page.
- libexpat_project · libexpat
References
- https://github.com/libexpat/libexpat/pull/1321ExploitPatchVendor Advisory
- https://www.vulncheck.com/advisories/expat-denial-of-service-via-storeatts-quadratic-complexityExploitPatchThird Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html