Echo: Encoded slash (%2F) bypasses route-level protection and exposes static files

Description

Echo is a Go web framework. Prior to 4.15.3 and 5.2.0, Echo's router and static file handler disagree on URL path decoding. The router matches routes using the raw encoded path (preserving %2F as-is), while StaticDirectoryHandler unescapes %2F to / before resolving filesystem paths. This allows an attacker to bypass route-level access controls and read static files without authorization. This vulnerability is fixed in 4.15.3 and 5.2.0.

Scores

EPSS (exploitation in 30 days)

0.52% · top 56% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: poc · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

• CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (opens in a new tab)All about CWE-22 and its CVEs

Affected products

• labstack · echo

  • affected < 4.15.3
  • affected >= 5.0.0, < 5.2.0

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• Gogithub.com/labstack/echoGHSA-vfp3-v2gw-7wfq (opens in a new tab)
• Gogithub.com/labstack/echo/v4GHSA-vfp3-v2gw-7wfq (opens in a new tab)
• Gogithub.com/labstack/echo/v5GHSA-vfp3-v2gw-7wfq (opens in a new tab)

References (1)

• https://github.com/labstack/echo/security/advisories/GHSA-vfp3-v2gw-7wfq (opens in a new tab)x_refsource_CONFIRMexploit

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-vfp3-v2gw-7wfq (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-55677](https://trackcve.app/badge/CVE-2026-55677.svg)](https://trackcve.app/cve/CVE-2026-55677)

Record last updated 26 Jun 2026, 16:50 UTC.