{"cve":"CVE-2026-64607","nvd":{"published":"2026-07-31T11:17:11.710","modified":"2026-10-23T23:10:00.157","status":"Modified","description":"HttpClient based on the classic i/o model fails to correctly release the underlying connection back to the connection manager if it encounters an invalid or unsupported `Content-Encoding` header value in the response message. Please note this defect does not affect HttpClient based on the async i/o model.\n\nThis issue affects Apache HttpComponents Client: from 5.0-alpha1 through 5.6.2.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-772"],"references":["https://lists.apache.org/thread/qqfzo3fqcdk4l5496vz95ppvl4ty511q","http://www.openwall.com/lists/oss-security/2026/08/13/5"],"products":["apache:httpclient"],"source":"nvd","synced_at":"2026-10-24T16:53:34.184483516+00:00"},"epss":{"cve":"CVE-2026-64607","score":0.00464,"percentile":0.39938,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-hjcp-jmpx-g3qm","url":"https://osv.dev/vulnerability/GHSA-hjcp-jmpx-g3qm","summary":"Apache HttpComponents Client: Connection Leak on Content-Encoding Decode Error Leads to Pool Exhaustion DoS","modified":"2026-09-10T03:50:12.358752934Z","packages":[{"ecosystem":"Maven","name":"org.apache.httpcomponents.client5:httpclient5","purl":"pkg:maven/org.apache.httpcomponents.client5/httpclient5","ranges":[">=5.0-alpha1 <5.6.3"],"fixed":["5.6.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}