# CVE-2026-62987: Fabio - Incomplete fix for CVE-2025-48865: operator-configured trust headers (clientip/tls/requestid) still strippable via the Connection header

> Attackers can strip operator-configured trust headers via the Connection header, bypassing backend authorization and auditing mechanisms in Fabio deployments.

- **Severity:** Medium 5.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** GHSA-fq95-v8xc-jm3v, GO-2026-6566, UBUNTU-CVE-2026-62987

## What is CVE-2026-62987?

CVE-2026-62987 is a medium-severity vulnerability in fabiolb fabio, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Fabio is an HTTP(S) and TCP router for deploying applications managed by consul. From 1.6.6 until 1.7.2, the CVE-2025-48865 fix in proxy/http_headers.go uses protectHeaders for a hardcoded set of forwarded headers but omits the operator-configured ClientIPHeader, TLSHeader, and RequestID names. In proxy/http_proxy.go, HTTPProxy.ServeHTTP calls addHeaders to set these trust headers before Go ReverseProxy processes the inbound Connection header, allowing an unauthenticated client to name and remove the configured headers before the request reaches the backend. Deployments that enable the corresponding proxy.header options can therefore lose client-IP, TLS-termination, or request-correlation signals used by backend authorization and auditing; the options are empty by default, and the hardcoded protected forwarded headers are unaffected. This issue is fixed in version 1.7.2.

Weakness: CWE-348 (Use of Less Trusted Source), CWE-290 (Authentication Bypass by Spoofing)

## Which versions are affected by CVE-2026-62987?

3 open source packages ship an affected version, including github.com/fabiolb/fabio.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/fabiolb/fabio` | Go | From 1.6.6 | 1.7.2 |
| `github.com/fabiolb/fabio` | Go | From 1.6.6 | 1.7.2 |
| `github.com/fabiolb/fabio` | Go | From 1.6.6 | 1.7.2 |

## How do I fix CVE-2026-62987?

Upgrade github.com/fabiolb/fabio to 1.7.2 or later.

## Is CVE-2026-62987 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62987 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-62987 and fix it if it is affected.

What it is: CVE-2026-62987 is a medium-severity vulnerability in fabiolb fabio, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62987 exists.

Affected packages and fixed versions:
- github.com/fabiolb/fabio (Go): affected from 1.6.6; fixed in 1.7.2
- github.com/fabiolb/fabio (Go): affected from 1.6.6; fixed in 1.7.2
- github.com/fabiolb/fabio (Go): affected from 1.6.6; fixed in 1.7.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-62987/ (Markdown: https://insights.sbomify.com/CVE-2026-62987/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-62987
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62987
- OSV: https://osv.dev/vulnerability/CVE-2026-62987

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-62987/
Summaries are generated and may contain mistakes; the official description above is the record.