Reference page — cumulative record through Thursday, October 8, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV N L N R U L N N 4.3 .0388 89.9 —
AFFECTED Product Versions Fixed n/a n/a – —
TIMELINE Jul 13 Reserved by mitre Jul 13 Published (CNA: mitre) Oct 7 EXPLOIT PUBLISHED — CVE-2018-20852. Public exploit reference added.
http.cookiejar.DefaultPolicy.domain_return_ok in Lib/http/cookiejar.py in Python before 3.7.3 does not correctly validate the domain: it can be tricked into sending existing cookies to the wrong server. An attacker may abuse this flaw by using a server with a hostname that has another valid hostname as a suffix (e.g., pythonicexample.com to steal cookies for example.com). When a program uses http.cookiejar.DefaultPolicy and tries to do an HTTP connection to an attacker-controlled server, existing cookies can be leaked to the attacker. This affects 2.x through 2.7.16, 3.x before 3.4.10, 3.5.x before 3.5.7, 3.6.x before 3.6.9, and 3.7.x before 3.7.3.
| Date | Event | Detail |
|---|---|---|
| July 13, 2019 | Reserved | Reserved by mitre |
| July 13, 2019 | Published | Published (CNA: mitre) |
| October 7, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2018-20852. Public exploit reference added. |
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|---|---|---|---|
| n/a | n/a | — | n/a | — |
Authoritative record: CVE-2018-20852 at cve.org
Weaknesses: CWE-20
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2018-20852 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Thursday, October 8, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
