Skip to main content
CVE-2026-118658VulnerabilityPublished

WWWRedirect/NonWWWRedirect Middlewares · V5: Echo has Arbitrary Scheme Injection

Affects github.com/labstack/echo/v5Source GCVE Database

0
Authoritative record:CVE-2026-118658· Medium 4.7

Not known to be exploited · CVSS 4.7 Medium : upgrade to 5.1.1 when convenient.

Data as of 28 Oct 2026, 22:12 UTC

CVSS 3.1 base score
4.7Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.1.1, 4.15.2
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 28 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade github.com/labstack/echo/v5 to 5.1.1; github.com/labstack/echo/v4 to 4.15.2.

Affected software

ProductAffectedFixed in
Gogithub.com/labstack/echo/v5Affected
  • <5.1.1
Fixed in
  • 5.1.1
Gogithub.com/labstack/echo/v4Affected
  • <4.15.2
Fixed in
  • 4.15.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

## Summary The `c.Scheme()` method in Echo (`context.go:162-181`) trusts the `X-Forwarded-Proto`, `X-Forwarded-Protocol`, and `X-Url-Scheme` request headers without validating that the value is `http` or `https`. The `WWWRedirect()` and `NonWWWRedirect()` middlewares use this unsanitized scheme to construct redirect URLs, allowing an attacker to inject arbitrary URI schemes into the `Location` response header. ## Affected Components - `context.go:162-181` - `Scheme()` method returns attacker-controlled value verbatim - `middleware/redirect.go:172-184` - `redirectWWW`/`redirectNonWWW` use unsanitized scheme ## Proof of Concept ``` GET /path HTTP/1.1 Host: example.com X-Forwarded-Proto: javascript Response: HTTP/1.1 301 Moved Permanently Location: javascript://www.example.com/path ``` Confirmed injectable schemes: `javascript`, `data`, `vbscript`, `file`, `ftp`, `ssh`, `telnet`, `gopher`. Only `WWWRedirect()` and `NonWWWRedirect()` (and `WithConfig` variants) are affected. `HTTPSRedirect`, `HTTPSWWWRedirect`, `HTTPSNonWWWRedirect` are NOT affected (they hardcode `https://`). ## Impact - Open redirect to arbitrary scheme URLs when app is not behind a proxy that strips `X-Forwarded-Proto` - Cache poisoning when behind a CDN that caches redirect responses keyed by path - `file://` scheme injection could trigger file access in some browser configurations ## Suggested Fix Whitelist scheme in `c.Scheme()` to only return `http` or `https`: ```go func (c *Context) Scheme() string { if c.IsTLS() { return "https" } if scheme := c.request.Header.Get(HeaderXForwardedProto); scheme != "" { scheme = strings.ToLower(strings.TrimSpace(scheme)) if scheme == "https" { return "https" } } return "http" } ``` ## Disclosure Source code review, manually verified with actual HTTP server. Tested on Echo v5.0.4 (latest master). ## Patches Fixed in `github.com/labstack/echo/v5` v5.1.1 and `github.com/labstack/echo/v4` v4.15.2. `Context.Scheme()` now accepts only `http`, `https`, `ws` or `wss` from the `X-Forwarded-Proto`, `X-Forwarded-Protocol` and `X-Url-Scheme` headers, and falls back to `http` for any other value (#2953). ## Workarounds Upgrade to a patched version. If you cannot upgrade, have your edge proxy overwrite or remove the `X-Forwarded-Proto`, `X-Forwarded-Protocol` and `X-Url-Scheme` request headers.

References

Community reviews

Loading reviews…