{"cve":"CVE-2026-50013","nvd":{"published":"2026-09-11T22:16:37.813","modified":"2026-09-30T19:57:08.043","status":"Deferred","description":"Hoverfly is an open source API simulation tool. Prior to version 1.12.8, when Hoverfly is running in Diff mode, the `AddDiff()` function writes to the shared `responsesDiff` map without any synchronization (no mutex). When multiple proxy requests are processed concurrently (the normal case for any proxy), the concurrent map writes trigger Go's built-in race detector which causes a `fatal error: concurrent map read and map write`, immediately killing the entire Hoverfly process. This is trivially exploitable by sending multiple simultaneous requests. Version 1.12.8 patches the issue.","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:H","score":7.5},"cwes":["CWE-362","CWE-820"],"references":["https://github.com/SpectoLabs/hoverfly/pull/1227","https://github.com/SpectoLabs/hoverfly/releases/tag/v1.12.8","https://github.com/SpectoLabs/hoverfly/security/advisories/GHSA-qrh4-p6v4-mrfg"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-50013","score":0.0047,"percentile":0.4042,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-qrh4-p6v4-mrfg","url":"https://osv.dev/vulnerability/GHSA-qrh4-p6v4-mrfg","summary":"Hoverfly: Process Crash via Concurrent Map Write Race Condition in Diff Mode","modified":"2026-07-21T19:19:02.899214091Z","packages":[{"ecosystem":"Go","name":"github.com/SpectoLabs/hoverfly","purl":"pkg:golang/github.com/SpectoLabs/hoverfly","ranges":["<1.12.8"],"fixed":["1.12.8"]}]},{"id":"GO-2026-5977","url":"https://osv.dev/vulnerability/GO-2026-5977","summary":"Hoverfly: Process Crash via Concurrent Map Write Race Condition in Diff Mode in github.com/SpectoLabs/hoverfly","modified":"2026-07-21T19:15:30.653551557Z","packages":[{"ecosystem":"Go","name":"github.com/SpectoLabs/hoverfly","purl":"pkg:golang/github.com/SpectoLabs/hoverfly","ranges":["<1.12.8"],"fixed":["1.12.8"]}]}],"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."]}