The expat and elementtree parsers use insufficient entropy for XML hash-flooding protection
Summary
| CVE | CVE-2026-7210 |
|---|---|
| State | PUBLISHED |
| Assigner | PSF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-11 18:16:42 UTC |
| Updated | 2026-05-12 14:20:56 UTC |
| Description | `xml.parsers.expat` and `xml.etree.ElementTree` use insufficient entropy for Expat hash-flooding protection, which allows a crafted XML document to trigger hash flooding.\r\n\r\nFully mitigating this vulnerability requires both updating libexpat to 2.8.0 or later and applying this patch. |
Risk And Classification
Primary CVSS: v4.0 6.3 MEDIUM from [email protected]
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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
EPSS: 0.000450000 probability, percentile 0.139240000 (date 2026-05-12)
Problem Types: CWE-331 | CWE-331 CWE-331 Insufficient entropy
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 6.3 | MEDIUM | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 6.3 | MEDIUM | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
HighAttack Requirements
NonePrivileges Required
NoneUser Interaction
NoneConfidentiality
NoneIntegrity
NoneAvailability
LowSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Python Software Foundation | CPython | affected 3.15.0 python | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| mail.python.org/archives/list/[email protected]/thread/PNY5OMBDPM2... | [email protected] | mail.python.org | |
| www.openwall.com/lists/oss-security/2026/05/11/13 | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | |
| github.com/python/cpython/pull/149023 | [email protected] | github.com | |
| www.openwall.com/lists/oss-security/2026/05/11/8 | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | |
| github.com/python/cpython/issues/149018 | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Stan Ulbrych (https://github.com/StanFromIreland) (en)
CNA: Gregory P. Smith (https://github.com/gpshead) (en)
There are currently no legacy QID mappings associated with this CVE.