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Response snapshot Nov 3, 2026, 01:01 UTC

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VulnerabilityCVE-2026-63667

ApostropheCMS: Arbitrary file read via import-export attachment-name path traversal

The @apostrophecms/import-export module reconstructs the on-disk source path of every imported attachment from JSON metadata contained in the uploaded archive. The archive carries an aposAttachments.

At a glance

Exploited
Not known
Severity
6.5 Medium (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: @apostrophecms/import-export: 3.6.2. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-79qf-vqgc-7xx3 (opens a new tab)

What happened

Summary

The @apostrophecms/import-export module reconstructs the on-disk source path of every imported attachment from JSON metadata contained in the uploaded archive.

The archive carries an aposAttachments.json file whose name and extension fields are concatenated into a filesystem path with no traversal check. The zip-slip guard that the module applies during tar extraction validates tar entry names only and does not cover this second path, which is built after extraction.

The file at the resulting path is read and copied into the public uploads directory, then served over HTTP without authentication. A ../ sequence in name makes the module read a file outside the extraction directory and publish it at an anonymous URL.

Continue reading

Result: an authenticated contributor reads any file on the host whose name ends in an allowlisted extension (other users' uploaded documents, text or CSV dumps, PDFs) by importing a crafted archive and fetching the planted attachment anonymously.

Affected

apostrophecms/apostrophe with the @apostrophecms/import-export module installed and registered. Module version 3.6.1, tested against Apostrophe 4.31.0 (monorepo HEAD 4d478d9). Requires an account with the contributor role or higher; guest and anonymous requests are rejected. The module is not part of the default starter kit, so sites that never installed it are not affected. Files whose real name lacks an accepted file-group extension are not reachable.

Root cause

The import parser builds each attachment's source path by concatenating attacker-controlled JSON fields: lib/formats/gzip.js:46 sets file.path = path.join(attachmentFilesPath, ${attachment._id}-${attachment.name}.${attachment.extension}) from the aposAttachments.json entries in the uploaded archive. That path flows unchanged through lib/methods/import.js:832 (insertAttachments) into lib/methods/import.

js:1074 (attachment.insert), where uploadfs copies the referenced file into the public uploads directory served by express.static. The archive's only traversal guard, lib/formats/gzip.js:143 (if (name.includes('../'))), validates tar entry names during extraction and never inspects the name/extension values used to construct the read path, so a name of ../../../../../../tmp/secret escapes attachmentFilesPath.

Reaching the sink requires only an authenticated session (lib/methods/import.js:71), view permission on the target type (lib/methods/index.js:54), and the upload-attachment permission enforced at modules/@apostrophecms/attachment/index.js:442, which the built-in contributor role holds. The trailing .${extension} is appended and checked against the file-group allowlist in modules/@apostrophecms/attachment/index.

js (getFileGroup), so the target file's real name must end in an accepted extension (txt, csv, pdf, xls, doc, svg, and similar).

Reproduction

Apostrophe 4.31.0 starter-kit-essentials, MongoDB, default roles, @apostrophecms/import-export 3.6.1 installed, local uploadfs backend.

1. Place a secret file outside the upload tree with an allowlisted extension.

$ cat /tmp/apos_victim_secret.txt
TOP-SECRET DB DUMP
DB_PASSWORD=Pr0d-Secret-9981
API_KEY=sk_live_victim_abcdef

2. Build a gzip archive whose aposAttachments.json points the attachment name at that file through traversal (aposDocs.json is []).

[{"_id":"evilatt0001","name":"../../../../../../../../../../../../tmp/apos_victim_secret","extension":"txt","title":"loot","docIds":[],"crops":[]}]

3. As a contributor, import the archive through the module's import action (POST /api/v1/@apostrophecms/ /import-export-import), then fetch the created attachment with no session.

$ curl -i http://localhost:3500/uploads/attachments/evilatt0001-apos-victim-secret.txt
HTTP/1.1 200 OK
Content-Type: text/plain; charset=UTF-8

TOP-SECRET DB DUMP
DB_PASSWORD=Pr0d-Secret-9981
API_KEY=sk_live_victim_abcdef

Live-verified: a contributor-driven import reads /tmp/apos_victim_secret.txt (outside the extraction directory) and serves it at an anonymous URL; the same import run as a guest is rejected at the upload-attachment check (modules/@apostrophecms/attachment/index.js:442).

Impact

- Read of arbitrary host files whose real name ends in an allowlisted extension (txt, csv, pdf, xls, doc, svg, and similar). - Disclosure of other users' uploaded documents and any allowlisted-extension file readable by the Node process. - The exfiltration target is copied to a public, unauthenticated URL. - Triggered by the contributor role in a single import, no admin interaction.

Credit

Jan Kahmen, [turingpoint](https://www.turingpoint.de) (jan@turingpoint.de)

Affected package ranges reported by GitHub: @apostrophecms/import-export: <= 3.6.1

Scores and how they were measured

CVSS base severity

6.5

Version 3.1As of

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

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-79qf-vqgc-7xx3 (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-79qf-vqgc-7xx3, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 2). ApostropheCMS: Arbitrary file read via import-export attachment-name path traversal (CVE-2026-63667). https://kevwire.com/record/CVE-2026-63667

MLA

"ApostropheCMS: Arbitrary file read via import-export attachment-name path traversal (CVE-2026-63667)." KEVWire, 2 Nov. 2026, kevwire.com/record/CVE-2026-63667.

Chicago

KEVWire. "ApostropheCMS: Arbitrary file read via import-export attachment-name path traversal (CVE-2026-63667)." Last modified November 2, 2026. https://kevwire.com/record/CVE-2026-63667.

Evidence summary (plain text)

ApostropheCMS: Arbitrary file read via import-export attachment-name path traversal (Sep 2, 2026).
The @apostrophecms/import-export module reconstructs the on-disk source path of every imported attachment from JSON metadata contained in the uploaded archive.

The archive carries an aposAttachments.json file whose name and extension fields are concatenated into a filesystem path with no traversal check. The zip-slip guard that the module applies during tar extraction validates tar entry names only and does not cover this second path, which is built after extraction.
CVSS 6.5 (version 3.1; evidence as of Nov 2, 2026; https://github.com/advisories/GHSA-79qf-vqgc-7xx3).
Sources:
GitHub-reviewed advisory GHSA-79qf-vqgc-7xx3: https://github.com/advisories/GHSA-79qf-vqgc-7xx3
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: CVE-2026-63667.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 3, 2026, 01:00 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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