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CVE-2026-59965 high CVSS 7.1

Authorization Flaw in @jhb.software/payload-alt-text-plugin (CVE-2026-59965)

Summary

Vulnerability in @jhb.software/payload-alt-text-plugin (CVE-2026-59965). Data can be tampered with by attackers. Exploitable via POST /api/alt-text-plugin/generate. Mitigation: upgrade to 0.8.0 or later.

Original description

The description as published by the source.

Alt Text Endpoint Authorization Bypass via Payload Local API overrideAccess Omission

Summary

@jhb.software/payload-alt-text-plugin v0.7.0 exposes custom Payload CMS endpoints (POST /api/alt-text-plugin/generate and /bulk) that call the Payload Local API (findByID and update) without setting overrideAccess: false. Because Payload's internal logic evaluates shouldOverrideAccess = overrideAccess !== false, omitting the parameter causes it to default to true, silently bypassing all collection-level access control functions. Any authenticated user — regardless of role — can read and overwrite the alt and keywords fields of arbitrary upload documents that would otherwise be protected by restrictive collection access rules. The vulnerability is rated High (CVSS 7.1).

Details

The plugin registers two network endpoints in alt-text/src/plugin.ts:179-186. Their default access guard (plugin.ts:55) only checks !!req.user, meaning any authenticated session satisfies the check regardless of the role required by the underlying collection.

The endpoint handler at alt-text/src/endpoints/generateAltText.ts accepts user-controlled id, collection, locale, and update fields from the request body (line 29), then passes them directly to two unsecured Local API calls:

Read bypass (generateAltText.ts:31):

const imageDoc = await req.payload.findByID({
  id,
  collection,
  depth: 0,
  // overrideAccess: false is absent → d…

Source: NIST National Vulnerability Database NVD GitHub Advisory

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-2026-59965 has been found in @jhb.software/payload-alt-text-plugin.
Attackers can target a specific entry point like POST /api/alt-text-plugin/generate over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 7.1/10.
What to do: upgrade @jhb.software/payload-alt-text-plugin to 0.8.0 or later.
If unsure, ask your IT team or search "@jhb.software/payload-alt-text-plugin CVE-2026-59965" on the vendor's site.

CVE-2026-59965 (@jhb.software/payload-alt-text-plugin) — CWE-863 / CVSS v3 7.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /api/alt-text-plugin/generate / overrideAccess / findByID / update
Patched: 0.8.0 — 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

Incorrect authorization (CWE-863) exists in @jhb.software/payload-alt-text-plugin. Attackers reach the vulnerable code path via POST /api/alt-text-plugin/generate.

📍 Affected scope

Check the vendor advisory for the affected versions of @jhb.software/payload-alt-text-plugin. Attack surface: POST /api/alt-text-plugin/generate / overrideAccess / findByID / update.

🔥 Severity

Severity: High (CVSS 7.1/10). Data can be tampered with by attackers.

🔧 How to fix

Update to 0.8.0.

🛡️ 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 POST /api/alt-text-plugin/generate requests with malformed payloads or SQL meta-characters. Run grep -r '@jhb.software/payload-alt-text-plugin' . 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 '@jhb.software/payload-alt-text-plugin' . | 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 @jhb.software/payload-alt-text-plugin 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 'POST /api/alt-text-plugin/generate' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで POST /api/alt-text-plugin/generate 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 @jhb.software/payload-alt-text-plugin to 0.8.0

    ステージング環境で 0.8.0 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 POST /api/alt-text-plugin/generate 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

npm @jhb.software/payload-alt-text-plugin
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.8.0"}]}]

References

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