vulnerability / NVI-00008902 / Revision 4
Echo: HTTPS Redirect and HSTS Bypass via Unconditional Trust of Forwarded Scheme Headers
GitHub lists this reviewed advisory for github.com/labstack/echo/v5, github.com/labstack/echo/v4. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
5.9 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
5.9 MEDIUM (3.1)
security-advisories@github.com severity; no combined Null risk score.
0.133%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.02835. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/labstack/echo/v5
source listed< 5.4.0
## Description `Context.Scheme()` unconditionally trusts four client-controlled HTTP headers to determine the request scheme, with no mechanism to configure trusted sources. This allows a remote unauthenticated attacker to bypass HTTPS redirect enforcement and suppress HSTS headers. The trusted headers (checked in this order of precedence): 1. `X-Forwarded-Proto` 2. `X-Forwarded-Protocol` 3. `X-Forwarded-Ssl` 4. `X-Url-Scheme` ### Threat model **Scenario A — Directly exposed application (vulnerable by default):** The Echo application listens on HTTP and is reachable directly by clients (no L7 proxy in front), or an attacker can bypass the proxy and reach the backend directly. In this case, the attacker has full control over all request headers. Sending `X-Forwarded-Proto: https` defeats the `HTTPSRedirect` middleware entirely — traffic stays on plaintext HTTP, enabling man-in-the-middle attacks. This is the primary scenario. The application is vulnerable by default with no misconfiguration required — simply using `e.Pre(middleware.HTTPSRedirect())` as documented is sufficient. **Scenario B — Behind L7 proxy with header sanitization (reduced risk):** If the application is stri
github.com/labstack/echo/v4
source listed< 4.16.0
## Description `Context.Scheme()` unconditionally trusts four client-controlled HTTP headers to determine the request scheme, with no mechanism to configure trusted sources. This allows a remote unauthenticated attacker to bypass HTTPS redirect enforcement and suppress HSTS headers. The trusted headers (checked in this order of precedence): 1. `X-Forwarded-Proto` 2. `X-Forwarded-Protocol` 3. `X-Forwarded-Ssl` 4. `X-Url-Scheme` ### Threat model **Scenario A — Directly exposed application (vulnerable by default):** The Echo application listens on HTTP and is reachable directly by clients (no L7 proxy in front), or an attacker can bypass the proxy and reach the backend directly. In this case, the attacker has full control over all request headers. Sending `X-Forwarded-Proto: https` defeats the `HTTPSRedirect` middleware entirely — traffic stays on plaintext HTTP, enabling man-in-the-middle attacks. This is the primary scenario. The application is vulnerable by default with no misconfiguration required — simply using `e.Pre(middleware.HTTPSRedirect())` as documented is sufficient. **Scenario B — Behind L7 proxy with header sanitization (reduced risk):** If the application is stri
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-2ffq-g2xg-c22p ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-118657 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-118657 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 4 ·
Source facts changed; compare the preserved prior revision.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.