Update dependency multer to v2 [SECURITY]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
multer	1.4.3 → 2.3.0

---

Multer vulnerable to Denial of Service via resource exhaustion

CVE-2026-2359 / GHSA-v52c-386h-88mc

More information

Details

Impact

A vulnerability in Multer versions < 2.1.0 allows an attacker to trigger a Denial of Service (DoS) by dropping connection during file upload, potentially causing resource exhaustion.

Patches

Users should upgrade to 2.1.0

Workarounds

None

Severity

• CVSS Score: 8.7 / 10 (High)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

• https://github.com/expressjs/multer/security/advisories/GHSA-v52c-386h-88mc
• https://nvd.nist.gov/vuln/detail/CVE-2026-2359
• https://github.com/expressjs/multer/commit/cccf0fe0e64150c4f42ccf6654165c0d66b9adab
• https://cna.openjsf.org/security-advisories.html
• https://www.cve.org/CVERecord?id=CVE-2026-2359
• https://github.com/advisories/GHSA-v52c-386h-88mc

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Multer vulnerable to Denial of Service via incomplete cleanup

CVE-2026-3304 / GHSA-xf7r-hgr6-v32p

More information

Details

Impact

A vulnerability in Multer versions < 2.1.0 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing resource exhaustion.

Patches

Users should upgrade to 2.1.0

Workarounds

None

Severity

• CVSS Score: 8.7 / 10 (High)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

• https://github.com/expressjs/multer/security/advisories/GHSA-xf7r-hgr6-v32p
• https://nvd.nist.gov/vuln/detail/CVE-2026-3304
• https://github.com/expressjs/multer/commit/739919097dde3921ec31b930e4b9025036fa74ee
• https://cna.openjsf.org/security-advisories.html
• https://www.cve.org/CVERecord?id=CVE-2026-3304
• https://github.com/advisories/GHSA-xf7r-hgr6-v32p

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Multer Vulnerable to Denial of Service via Uncontrolled Recursion

CVE-2026-3520 / GHSA-5528-5vmv-3xc2

More information

Details

Impact

A vulnerability in Multer versions < 2.1.1 allows an attacker to trigger a Denial of Service (DoS) by sending malformed requests, potentially causing stack overflow.

Patches

Users should upgrade to 2.1.1

Workarounds

None

Resources

• GHSA-5528-5vmv-3xc2
• https://www.cve.org/CVERecord?id=CVE-2026-3520
• expressjs/multer@7e66481
• https://cna.openjsf.org/security-advisories.html

Severity

• CVSS Score: 8.7 / 10 (High)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

• https://github.com/expressjs/multer/security/advisories/GHSA-5528-5vmv-3xc2
• https://nvd.nist.gov/vuln/detail/CVE-2026-3520
• https://github.com/expressjs/multer/commit/7e66481f8b2e6c54b982b34c152479e096ce2752
• https://cna.openjsf.org/security-advisories.html
• https://www.cve.org/CVERecord?id=CVE-2026-3520
• https://github.com/advisories/GHSA-5528-5vmv-3xc2

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Multer vulnerable to Denial of Service via deeply nested field names

CVE-2026-5079 / GHSA-72gw-mp4g-v24j

More information

Details

Impact

Multer is vulnerable to a Denial of Service (DoS) via deeply nested field names in multipart form data. The append-field dependency parses bracket notation in field names (e.g., a[b][c]) with no limit on nesting depth, allowing an attacker to force allocation of deeply nested object structures that consume CPU and memory. A single HTTP request with a crafted multipart body is sufficient to exploit this.

Patches

Users should upgrade to 2.2.0 and configure limits.fieldNestingDepth to the minimum depth their application requires.

Workarounds

Set limits.fields to a reasonable value to reduce the number of fields an attacker can send per request. This does not fully mitigate the issue but limits the impact.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/expressjs/multer/security/advisories/GHSA-72gw-mp4g-v24j
• https://nvd.nist.gov/vuln/detail/CVE-2026-5079
• https://cna.openjsf.org/security-advisories.html
• https://github.com/advisories/GHSA-72gw-mp4g-v24j

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

multer vulnerable to Denial of Service via crafted multipart field names

CVE-2026-77078 / GHSA-wc9g-mqfw-jrwm

More information

Details

Impact

A vulnerability in multer allows a remote, unauthenticated attacker to crash the Node.js process with a single multipart/form-data request. Two specially crafted text field names cause an uncaught RangeError: Invalid array length inside multer's field parsing, which is not routed to the application error handler and terminates the process. All applications using multer to parse multipart requests are affected.

Patches

Users should upgrade to 2.3.0.

Workarounds

None.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/expressjs/multer/security/advisories/GHSA-wc9g-mqfw-jrwm
• https://nvd.nist.gov/vuln/detail/CVE-2026-77078
• https://github.com/expressjs/multer/commit/87a584e8c8d4da873292635fa1d8c4d78d985b76
• https://cna.openjsf.org/security-advisories.html
• https://github.com/expressjs/multer/releases/tag/v2.3.0
• https://github.com/advisories/GHSA-wc9g-mqfw-jrwm

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

multer vulnerable to Denial of Service via oversized array index in field names

CVE-2026-82333 / GHSA-535w-7cp7-47q4

More information

Details

Impact

multer is vulnerable to a Denial of Service (DoS) via a crafted array index in multipart field names. The append-field dependency parses bracket notation in field names, and a large numeric index such as items[4294967294] forces allocation of a maximum-length sparse array. A following field with a non-numeric key on the same base then converts that array to an object by iterating its full length, which consumes CPU synchronously and leaves the process unable to handle other requests. A single HTTP request with a crafted multipart body is sufficient to exploit this, and it affects multer 1.x and 2.x.

Patches

Users should upgrade to 2.3.0 and configure limits.fieldArrayIndexLimit to the minimum array index their application requires.

Workarounds

None.

Severity

• CVSS Score: 7.5 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

• https://github.com/expressjs/multer/security/advisories/GHSA-535w-7cp7-47q4
• https://nvd.nist.gov/vuln/detail/CVE-2026-82333
• https://github.com/expressjs/multer/pull/1438
• https://github.com/expressjs/multer/commit/73c1759fa93b87366bc6dbd7abe1b80ddff7d27c
• https://cna.openjsf.org/security-advisories.html
• https://github.com/expressjs/multer/releases/tag/v2.3.0
• https://github.com/advisories/GHSA-535w-7cp7-47q4

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

multer vulnerable to file size limit bypass via async fileFilter race condition

CVE-2026-77063 / GHSA-qvfw-j98x-7q72

More information

Details

Impact

When multer is configured with an asynchronous fileFilter, the limits.fileSize limit can be bypassed. The 'limit' event is registered inside the async fileFilter callback, so if a file exceeds limits.fileSize before that callback runs, the event is missed and the oversized upload is accepted instead of being rejected with a LIMIT_FILE_SIZE error. Applications that rely on limits.fileSize to reject oversized uploads are affected on all upload methods (.single(), .array(), .fields(), .any()). Uploads using a synchronous fileFilter are not affected.

Patches

Users should upgrade to 2.3.0.

Workarounds

Use a synchronous fileFilter, or validate the uploaded file size after the upload completes.

Severity

• CVSS Score: 3.7 / 10 (Low)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

References

• https://github.com/expressjs/multer/security/advisories/GHSA-qvfw-j98x-7q72
• https://nvd.nist.gov/vuln/detail/CVE-2026-77063
• https://github.com/expressjs/multer/commit/ab6aeae650328cf31799dcfa4c3e116ba8faaacc
• https://cna.openjsf.org/security-advisories.html
• https://github.com/expressjs/multer/releases/tag/v2.3.0
• https://github.com/advisories/GHSA-qvfw-j98x-7q72

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Release Notes

expressjs/multer (multer)

v2.3.0

Compare Source

• Fix CVE-2026-77078 (GHSA-wc9g-mqfw-jrwm)
• Fix CVE-2026-77037 (GHSA-qfvm-cv95-jqjf)
• Fix CVE-2026-77063 (GHSA-qvfw-j98x-7q72)
• Fix CVE-2026-82333 (GHSA-535w-7cp7-47q4)
• Add MulterError codes INVALID_FIELD_NAME and STREAM_DESTROYED
• Add opt-in limits.fieldArrayIndexLimit to bound numeric array indexes in field names (#​1438)
• Accept files whose size is exactly limits.fileSize (#​1407)
• Preserve the caller's async context (AsyncLocalStorage) when calling next() (#​1124)
• Decode WHATWG-escaped characters (%0A, %0D, %22) in file.originalname (#​1421)
• Do not crash when fileFilter invokes its callback more than once (#​1427)
• Use a fallback message for MulterError codes without a mapping (#​1448)
• Docs: clarify preservePath and parts, use crypto.randomBytes in the DiskStorage example (#​1414, #​1430, #​1436)
• Docs: add Indonesian, Japanese and Tamil translations and refresh all translations from the current README (#​1431, #​1354, #​1462)
• Internal: run the test suite on Windows (#​1334)

v2.2.0

Compare Source

• Fix CVE-2026-5038 (GHSA-3p4h-7m6x-2hcm)
• Fix CVE-2026-5079 (GHSA-72gw-mp4g-v24j)

v2.1.1

Compare Source

• Fix CVE-2026-3520 (GHSA-5528-5vmv-3xc2)
• fix error/abort handling

v2.1.0

Compare Source

• Add defParamCharset option for UTF-8 filename support (#​1210)
• Fix CVE-2026-2359 (GHSA-v52c-386h-88mc)
• Fix CVE-2026-3304 (GHSA-xf7r-hgr6-v32p)

v2.0.2

Compare Source

• Fix CVE-2025-7338 (GHSA-fjgf-rc76-4x9p)

v2.0.1

Compare Source

• Fix CVE-2025-48997 (GHSA-g5hg-p3ph-g8qg)

v2.0.0

Compare Source

• Breaking change: The minimum supported Node version is now 10.16.0
• Fix CVE-2025-47935 (GHSA-44fp-w29j-9vj5)
• Fix CVE-2025-47944 (GHSA-4pg4-qvpc-4q3h)

v1.4.4

Compare Source

• Bugfix: Bump busboy to fix CVE-2022-24434 (#​1097)
• Breaking: Require Node.js 10.16.0 or later (#​1097)

---

Configuration

📅 Schedule: (UTC)

• Branch creation
  • At any time (no schedule defined)
• Automerge
  • At any time (no schedule defined)

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• If you want to rebase/retry this PR, check this box

---

This PR was generated by Mend Renovate. View the repository job log.