---
title: "CVE-2026-0650: OpenFlagr contains an authentication bypass vulnerability in the HTTP middleware"
url: https://erroneo.us/security/cve/CVE-2026-0650/
description: "CVE-2026-0650 (github.com/openflagr/flagr (Go)): OpenFlagr versions prior to and including 1.1.18 contain an authentication bypass vulnerability in the HTTP…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-01-07
date_modified: 2026-10-08
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-0650"
kev: false
cvss: 9.3
epss: 0.01519
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-0650: OpenFlagr contains an authentication bypass vulnerability in the HTTP middleware

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 1.5% , percentile 74: FIRST’s model estimates a 1.5% chance of exploitation activity in the next 30 days, higher than 74% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/openflagr/flagr (Go) < 0.0.0-20251009103504-fe83dc87aa40, fixed in 0.0.0-20251009103504-fe83dc87aa40 . Check your lockfile, including transitive dependencies.

## What it is

OpenFlagr versions prior to and including 1.1.18 contain an authentication bypass vulnerability in the HTTP middleware. Due to improper handling of path normalization in the whitelist logic, crafted requests can bypass authentication and access protected API endpoints without valid credentials. Unauthorized access may allow modification of feature flags and export of sensitive data.

## Affected packages

- Go `github.com/openflagr/flagr` < 0.0.0-20251009103504-fe83dc87aa40 → fixed: 0.0.0-20251009103504-fe83dc87aa40

## Affected products (CVE record)

- OpenFlagr Flagr: <= 1.1.18

## Severity

- VulnCheck CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.52% probability of exploitation activity in the next 30 days; percentile 74.

## Sources

- [github.com](https://github.com/openflagr/flagr/releases/tag/1.1.19)
- [GitHub Advisory GHSA-rwp9-5g7q-73q3](https://github.com/advisories/GHSA-rwp9-5g7q-73q3)
- [CVE.org record CVE-2026-0650](https://www.cve.org/CVERecord?id=CVE-2026-0650)
- [NVD entry CVE-2026-0650](https://nvd.nist.gov/vuln/detail/CVE-2026-0650)
- [dreyand.rs](https://dreyand.rs/code%20review/golang/2026/01/03/0day-speedrun-openflagr-less-1118-authentication-bypass)
- [vulncheck.com](https://www.vulncheck.com/advisories/openflagr-authentication-bypass-via-prefix-whitelist-path-normalization)
- [github.com](https://github.com/openflagr/flagr/commit/fe83dc87aa404a57554aa5839ac450f55c203570)

---
Source page: https://erroneo.us/security/cve/CVE-2026-0650/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt