CVE-2026-55677

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

HIGH
7.5
CVSS Score
Published: June 26, 2026 at 04:15 PM UTC
Updated: October 25, 2026 at 05:10 PM UTC
1 product affected across 1 vendorEcho

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Severity
HIGH7.5
Exploit prediction
EPSS 0.5%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Affected range stops below 4.15.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.2.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-22

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