# Fabio - Incomplete fix for CVE-2025-48865: operator-configured trust headers (clientip/tls/requestid) still strippable via the Connection header

Advisory record · `GHSA-fq95-v8xc-jm3v`

- **Identifiers:** `GHSA-fq95-v8xc-jm3v` · `CVE-2026-62987` · `GO-2026-6566`
- **State:** Confirmed
- **Severity:** CVSS 5.8 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-290](https://cwe.mitre.org/data/definitions/290.html) · [CWE-348](https://cwe.mitre.org/data/definitions/348.html)
- **Tags:** [Authentication bypass](https://agentprime.io/advisories/tag/auth-bypass.md) · [CWE-348](https://agentprime.io/advisories/tag/cwe-348.md)
- **Published:** 22 Sept 2026
- **Updated:** 1 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 22 Sept 2026, 20:34 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `github.com/fabiolb/fabio` (Go): affected `>=1.6.6, <1.7.2`; fixed in `1.7.2`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Fabio versions 1.6.6 through 1.7.1 are affected. When an operator enables the client IP, TLS, or request ID headers, a remote unauthenticated client can list those header names in the Connection header, causing the proxy to strip them before the request reaches the backend. A backend relying on those headers could then see a spoofed or missing client IP, incorrect TLS status, or lost request correlation. Upgrade to Fabio 1.7.2, which is the fixed version.

Written 1 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.8 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0020, the 10th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:12 UTC: First seen by agentprime
- 31 Oct 2026, 14:12 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-fq95-v8xc-jm3v)

## Sources

- [GitHub Advisory Database: GHSA-fq95-v8xc-jm3v](https://github.com/advisories/GHSA-fq95-v8xc-jm3v)
- [OSV: GHSA-fq95-v8xc-jm3v](https://osv.dev/vulnerability/GHSA-fq95-v8xc-jm3v)
- <https://github.com/fabiolb/fabio/security/advisories/GHSA-fq95-v8xc-jm3v>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-62987>
- <https://github.com/fabiolb/fabio/commit/240526a8004077edad4fb96d25b382bfc3901357>
- <https://github.com/fabiolb/fabio>
- <https://github.com/fabiolb/fabio/releases/tag/v1.7.2>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-fq95-v8xc-jm3v>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-fq95-v8xc-jm3v/>. Everything for agents: <https://agentprime.io/llms.txt>.