{"cve":"CVE-2023-39326","nvd":{"published":"2023-12-06T17:15:07.147","modified":"2026-06-17T06:12:02.453","status":"Modified","description":"A malicious HTTP sender can use chunk extensions to cause a receiver reading from a request or response body to read many more bytes from the network than are in the body. A malicious HTTP client can further exploit this to cause a server to automatically read a large amount of data (up to about 1GiB) when a handler fails to read the entire body of a request. Chunk extensions are a little-used HTTP feature which permit including additional metadata in a request or response body sent using the chunked encoding. The net/http chunked encoding reader discards this metadata. A sender can exploit this by inserting a large metadata segment with each byte transferred. The chunk reader now produces an error if the ratio of real body to encoded bytes grows too small.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","score":5.3},"cwes":[],"references":["https://go.dev/cl/547335","https://go.dev/issue/64433","https://groups.google.com/g/golang-dev/c/6ypN5EjibjM/m/KmLVYH_uAgAJ","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UIU6HOGV6RRIKWM57LOXQA75BGZSIH6G/","https://pkg.go.dev/vuln/GO-2023-2382"],"products":["golang:go"],"source":"nvd","synced_at":"2026-10-19T21:42:34.585441961+00:00"},"epss":{"cve":"CVE-2023-39326","score":0.01208,"percentile":0.68381,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GO-2023-2382","url":"https://osv.dev/vulnerability/GO-2023-2382","summary":"Denial of service via chunk extensions in net/http","modified":"2026-02-04T03:33:11.274886Z","packages":[{"ecosystem":"Go","name":"stdlib","purl":"pkg:golang/stdlib","ranges":["<1.20.12",">=1.21.0-0 <1.21.5"],"fixed":["1.20.12","1.21.5"]}]}],"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."]}