VulnerabilityPublished 28 Oct 2026

CVE-2026-118650: labstack echo · Improper Handling of URL Encoding

Affects labstack echoSource CVE Database V5

Not known to be exploited · CVSS 7.5 High : upgrade to 5.4.0 or 4.16.0 soon.

Data as of 28 Oct 2026, 19:57 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 5.4.0, 4.16.0

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade echo and github.com/labstack/echo to 5.4.0 or 4.16.0.

Affected software

Product	Affected	Fixed in
labstackecho	Affected >=5.0.0 <5.4.0	Fixed in 5.4.0
labstackecho	Affected <4.16.0	Fixed in 4.16.0
Gogithub.com/labstack/echo`pkg:golang/github.com/labstack/echo`Other threats	Affected <4.16.0 >=5.0.0 <5.4.0	Fixed in 4.16.0 5.4.0

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

AI-suggested

Upgrade labstack Echo to version 4.16.0 or later in the 4.x series, or 5.4.0 or later in the 5.x series, where this vulnerability is fixed. No other mitigations are indicated by the vendor advisory.

Description

CVE-2026-118650 is a vulnerability in the labstack Echo Go web framework affecting versions prior to 4.16.0 and 5.4.0. It involves improper handling of URL encoding in the globally mounted middleware.Static instance, where the static handler decodes the URL path differently than the router, leading to inconsistent route protection. This discrepancy can allow an encoded slash to resolve to files under the static root unexpectedly. The issue is fixed in versions 4.16.0 and 5.4.0.

Impact

An attacker can exploit this vulnerability to access files under the static root directory by using encoded URL paths that bypass route or group guards. The impact is confidentiality loss (high severity) as unauthorized file access is possible without authentication or user interaction. There is no impact on integrity or availability reported.

Summary

The labstack Echo framework prior to versions 4.16.0 and 5.4.0 has a vulnerability (CWE-177) due to inconsistent handling of URL encoding between the router and the globally mounted static middleware. The router matches the still-encoded path, while the static middleware decodes the URL.Path before matching. This inconsistency can cause an encoded slash (%2F) in the request path to bypass intended route or group guards, potentially exposing files under the static root that should be protected. The vulnerability is addressed by synchronizing the path handling in versions 4.16.0 and 5.4.0.

CWE-177Improper Handling of URL Encoding (Hex Encoding) (opens in a new tab)
Variant weakness
The product does not properly handle when all or part of an input has been URL encoded.
Architecture and Design · Input Validation
Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V1.5.1 (opens in a new tab)
Attack patterns
Double Encoding (opens in a new tab)
Generic Cross-Browser Cross-Domain Theft (opens in a new tab)
Using Slashes and URL Encoding Combined to Bypass Validation Logic (opens in a new tab)
URL Encoding (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-863Incorrect Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #17OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Oct 2026, 19:43 UTC

WeaknessesCWE-177, CWE-863

Technical details

References

Community reviews

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