Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-27469

Vulnerability in isso (CVE-2026-27469)

Summary

Vulnerability in isso (CVE-2026-27469). Risk of unauthorized operations or information disclosure. Exploitable via PUT /id/. Mitigation: upgrade to 0.13.2 or later.

Original description

The description as published by the source.

Impact

This is a stored Cross-Site Scripting (XSS) vulnerability affecting the website and author comment fields. The website field was HTML-escaped using quote=False, which left single and double quotes unescaped. Since the frontend inserts the website value directly into a single-quoted href attribute via string concatenation, a single quote in the URL breaks out of the attribute context, allowing injection of arbitrary event handlers (e.g. onmouseover, onclick).

The same escaping was missing entirely from the user-facing comment edit endpoint (PUT /id/) and the moderation edit endpoint (POST /id//edit/).

Any visitor to a page embedding isso comments is impacted. No authentication or interaction beyond mouse movement is required to trigger a payload — an attacker can post a comment anonymously (moderation is off by default) with a crafted website URL, and the payload persists in the database and fires on every page load. With the full-page invisible overlay technique described in the report, the victim only needs to move their mouse.

Patches

The issue is fixed in commit 3cf27c2. Users should upgrade to a version containing that commit once released. The fix applies html.escape(..., quote=True) to the website field across all three write paths (POST /new, PUT /id/, POST /id//edit/), and adds input validation and escaping to the moderation edit endpoint which previously had neither.

Workarounds

Enabling comment moderation (moderation = enabled = true in isso…

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-27469 has been found in isso.
Attackers can target a specific entry point like PUT /id/ over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade isso to 0.13.2 or later.
If unsure, ask your IT team or search "isso CVE-2026-27469" on the vendor's site.

CVE-2026-27469 (isso) — CWE-116
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: PUT /id/ / POST /id/ / POST /new
Patched: 0.13.2 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-116) exists in isso. Attackers reach the vulnerable code path via PUT /id/ without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of isso. Attack surface: PUT /id/ / POST /id/ / POST /new.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 0.13.2.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual PUT /id/ requests with malformed payloads or SQL meta-characters. Run grep -r 'isso' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'isso' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で isso を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Hunt for indicators of compromise detect 
    grep 'PUT /id/' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで PUT /id/ への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。

  3. 3
    Apply patch patch 
    Upgrade isso to 0.13.2

    ステージング環境で 0.13.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。

  4. 4
    Post-deployment verification verify 
    Replay attack against PUT /id/ on staging to confirm patch closes the vector

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。

Affected packages

PyPI isso
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.13.2"}]}]

References

We use cookies for analytics and ad measurement. This setting applies to all Game co., Ltd. sites. Details