# CVE-2026-116188: rclone serve s3 1.75.0 before 1.75.2 Memory Limit Bypass via Multipart Overflow

Status: published. Published: 2026-10-25. Updated: 2026-11-04.

rclone serve s3 versions 1.75.0 before 1.75.2 contain an integer overflow vulnerability in multipart reorder-memory accounting that bypasses the configured buffer limit. Attackers can open two concurrent current-part PUT requests declaring huge lengths to wrap the signed int64 counter and retain out-of-order parts in memory, exhausting the host.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- rclone / rclone (github.com/rclone/rclone): ≥ 1.75.0; < 1.75.2 (affected, semver); 1.75.2 (unaffected, semver). Source: CNA: VulnCheck

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:rclone:rclone:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "1.75.2",
            "versionStartIncluding": "1.75.0",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L; source: CNA: VulnCheck

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 5.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.25% as of 2026-11-04; percentile 16.94%

- SSVC: exploitation poc; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-190

## Exploit evidence

- exploit: https://github.com/rclone/rclone/security/advisories/GHSA-qjw8-8hmp-c3m6 (ADP: CISA-ADP)

## References

- https://github.com/rclone/rclone/security/advisories/GHSA-qjw8-8hmp-c3m6 (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/rclone-serve-s3-1.75.0-before-1.75.2-memory-limit-bypass-via-multipart-overflow (CNA: VulnCheck; third-party-advisory)

- https://github.com/rclone/rclone/security/advisories/GHSA-qjw8-8hmp-c3m6 (ADP: CISA-ADP; exploit)

- https://github.com/rclone/rclone/security/advisories/GHSA-qjw8-8hmp-c3m6 (disclosure@vulncheck.com; Vendor Advisory)

- https://www.vulncheck.com/advisories/rclone-serve-s3-1.75.0-before-1.75.2-memory-limit-bypass-via-multipart-overflow (disclosure@vulncheck.com; Third Party Advisory)

- https://github.com/rclone/rclone/security/advisories/GHSA-qjw8-8hmp-c3m6 (134c704f-9b21-4f2e-91b3-4a467353bcc0; Vendor Advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-116188; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-116188; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-116188; retrieved 2026-11-04; source updated Not reported

Revision: 04cb2ace39f84be51b647d631b2df06fe5ee450a4e2dddb02efd1fdbdbe2d4ae

Canonical: https://y2.dev/cve/CVE-2026-116188

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.