Vulnerability-Lookup

UBUNTU-CVE-2026-27587 (CVE-2026-27587)

Vulnerability from osv_ubuntu – Published: 2026-02-24 17:29 – Updated: 2026-07-02 16:11 – Source website

Details

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP path request matcher is intended to be case-insensitive, but when the match pattern contains percent-escape sequences (%xx) it compares against the request's escaped path without lowercasing. An attacker can bypass path-based routing and any access controls attached to that route by changing the casing of the request path. Version 2.11.1 contains a fix for the issue.

Severity

7.7 (High)


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

9.1 (Critical)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-27587	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-27587	REPORT
	https://github.com/caddyserver/caddy/security/adv…	REPORT
	https://github.com/caddyserver/caddy/releases/tag…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "caddy",
            "binary_version": "2.6.2-6ubuntu0.24.04.3+esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "caddy",
        "purl": "pkg:deb/ubuntu/caddy@2.6.2-6ubuntu0.24.04.3+esm2?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.6.2-6",
        "2.6.2-6ubuntu0.24.04.1",
        "2.6.2-6ubuntu0.24.04.2",
        "2.6.2-6ubuntu0.24.04.2+esm1",
        "2.6.2-6ubuntu0.24.04.3",
        "2.6.2-6ubuntu0.24.04.3+esm1",
        "2.6.2-6ubuntu0.24.04.3+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "caddy",
            "binary_version": "2.6.2-12"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "caddy",
        "purl": "pkg:deb/ubuntu/caddy@2.6.2-12?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.6.2-9",
        "2.6.2-11",
        "2.6.2-12"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "caddy",
            "binary_version": "2.6.2-14ubuntu0.26.04.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:26.04:LTS",
        "name": "caddy",
        "purl": "pkg:deb/ubuntu/caddy@2.6.2-14ubuntu0.26.04.1~esm1?arch=source\u0026distro=esm-apps/resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.6.2-12",
        "2.6.2-14",
        "2.6.2-14ubuntu0.26.04.1~esm1"
      ]
    }
  ],
  "aliases": [],
  "details": "Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy\u0027s HTTP `path` request matcher is intended to be case-insensitive, but when the match pattern contains percent-escape sequences (`%xx`) it compares against the request\u0027s escaped path without lowercasing. An attacker can bypass path-based routing and any access controls attached to that route by changing the casing of the request path. Version 2.11.1 contains a fix for the issue.",
  "id": "UBUNTU-CVE-2026-27587",
  "modified": "2026-07-02T16:11:59Z",
  "published": "2026-02-24T17:29:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-27587"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-27587"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/caddyserver/caddy/security/advisories/GHSA-g7pc-pc7g-h8jh"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/caddyserver/caddy/releases/tag/v2.11.1"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-27587"
  ]
}

CVE-2026-27587 (GCVE-0-2026-27587)

Vulnerability from cvelistv5 – Published: 2026-02-24 16:26 – Updated: 2026-02-27 20:48

Title

Caddy: MatchPath %xx (escaped-path) branch skips case normalization, enabling path-based route/auth bypass

Summary

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `path` request matcher is intended to be case-insensitive, but when the match pattern contains percent-escape sequences (`%xx`) it compares against the request's escaped path without lowercasing. An attacker can bypass path-based routing and any access controls attached to that route by changing the casing of the request path. Version 2.11.1 contains a fix for the issue.

Severity

7.7 (High)


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

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-02-27 20:47 UTC

CWE

CWE-178 - Improper Handling of Case Sensitivity

Assigner

GitHub_M mitre root

References

2 references

URL	Tags
https://github.com/caddyserver/caddy/security/adv…	x_refsource_CONFIRM
https://github.com/caddyserver/caddy/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
caddyserver	caddy	Affected: < 2.11.1

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-27587",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-27T20:47:59.330355Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-02-27T20:48:09.775Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "caddy",
          "vendor": "caddyserver",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.11.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy\u0027s HTTP `path` request matcher is intended to be case-insensitive, but when the match pattern contains percent-escape sequences (`%xx`) it compares against the request\u0027s escaped path without lowercasing. An attacker can bypass path-based routing and any access controls attached to that route by changing the casing of the request path. Version 2.11.1 contains a fix for the issue."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "HIGH"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-178",
              "description": "CWE-178: Improper Handling of Case Sensitivity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-24T16:26:40.222Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/caddyserver/caddy/security/advisories/GHSA-g7pc-pc7g-h8jh",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/caddyserver/caddy/security/advisories/GHSA-g7pc-pc7g-h8jh"
        },
        {
          "name": "https://github.com/caddyserver/caddy/releases/tag/v2.11.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/caddyserver/caddy/releases/tag/v2.11.1"
        }
      ],
      "source": {
        "advisory": "GHSA-g7pc-pc7g-h8jh",
        "discovery": "UNKNOWN"
      },
      "title": "Caddy: MatchPath %xx (escaped-path) branch skips case normalization, enabling path-based route/auth bypass"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-27587",
    "datePublished": "2026-02-24T16:26:40.222Z",
    "dateReserved": "2026-02-20T17:40:28.450Z",
    "dateUpdated": "2026-02-27T20:48:09.775Z",
    "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.

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

UBUNTU-CVE-2026-27587 (CVE-2026-27587)

CVE-2026-27587 (GCVE-0-2026-27587)

Tags

Sightings

Nomenclature

Related by attack behaviour