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GHSA-X6MJ-8JX9-QHQV

Vulnerability from github – Published: 2026-11-12 23:44 – Updated: 2026-11-12 23:44

Summary

Action Pack: Possible sensitive session information leak in Active Storage proxy mode

Details

Impact

When ActionDispatch::Cookies reads a signed or encrypted cookie that was written under a rotated secret (config.action_dispatch.cookies_rotations) or in the format that a :hybrid cookie serializer migrates from, it writes the cookie back to the response in the current format, and that write ignores request.session_options[:skip]. ActiveStorage::DisableSession relies on that option to keep the session cookie off the public, immutable responses of the Active Storage proxy controllers, but those controllers still load the session, so a request carrying an old-format session cookie could receive the rewritten session cookie in Set-Cookie on a cacheable response. A shared cache that stores such a response together with its Set-Cookie header could then serve one user's session to later requesters of the same URL, or serve an attacker's session to other users.

Applications are affected when they serve Active Storage files through the proxy controllers, have a cookie rotation or a :hybrid serializer migration configured, and run behind a cache that stores Set-Cookie on public responses. This is a path around the fix for CVE-2024-26144.

Details

In the fixed releases, a response that skips the session leaves an old-format signed or encrypted cookie unchanged, and the next request that does not skip the session upgrades it. An application that skips the session on every request no longer upgrades its signed or encrypted cookies. Cookies that the application sets explicitly are still written. See the Action Pack CHANGELOG.

Workarounds

Configure caching proxies not to store responses that carry a Set-Cookie header, or complete the cookie rotation or serializer migration and remove it from the configuration.

Releases

The fixed releases are available at the normal locations.

Patches for those who cannot upgrade at once: - 8.1: https://github.com/rails/rails/commit/849a6c30eacbb6ca4722132f43c4333a93188556.patch - 8.0: https://github.com/rails/rails/commit/0e6cf8faa89caf4c64311d35ca2bc88c1458d4e3.patch

Credit

This issue was responsibly reported by HackerOne researcher flashmyname.

Severity

6.8 (Medium)


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

Show details on source website

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "actionpack"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.1.0.beta1"
            },
            {
              "fixed": "8.1.4.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "actionpack"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0.5.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-126077"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-11-12T23:44:39Z",
    "nvd_published_at": "2026-11-10T21:19:26Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\nWhen `ActionDispatch::Cookies` reads a signed or encrypted cookie that was written under a rotated secret (`config.action_dispatch.cookies_rotations`) or in the format that a `:hybrid` cookie serializer migrates from, it writes the cookie back to the response in the current format, and that write ignores `request.session_options[:skip]`. `ActiveStorage::DisableSession` relies on that option to keep the session cookie off the public, immutable responses of the Active Storage proxy controllers, but those controllers still load the session, so a request carrying an old-format session cookie could receive the rewritten session cookie in `Set-Cookie` on a cacheable response. A shared cache that stores such a response together with its `Set-Cookie` header could then serve one user\u0027s session to later requesters of the same URL, or serve an attacker\u0027s session to other users.\n\nApplications are affected when they serve Active Storage files through the proxy controllers, have a cookie rotation or a `:hybrid` serializer migration configured, and run behind a cache that stores `Set-Cookie` on public responses. This is a path around the fix for [CVE-2024-26144](https://github.com/advisories/GHSA-8h22-8cf7-hq6g).\n\n### Details\nIn the fixed releases, a response that skips the session leaves an old-format signed or encrypted cookie unchanged, and the next request that does not skip the session upgrades it. An application that skips the session on every request no longer upgrades its signed or encrypted cookies. Cookies that the application sets explicitly are still written. See the Action Pack CHANGELOG.\n\n### Workarounds\nConfigure caching proxies not to store responses that carry a `Set-Cookie` header, or complete the cookie rotation or serializer migration and remove it from the configuration.\n\n### Releases\nThe fixed releases are available at the normal locations.\n\nPatches for those who cannot upgrade at once:\n- 8.1: https://github.com/rails/rails/commit/849a6c30eacbb6ca4722132f43c4333a93188556.patch\n- 8.0: https://github.com/rails/rails/commit/0e6cf8faa89caf4c64311d35ca2bc88c1458d4e3.patch\n\n### Credit\nThis issue was responsibly reported by HackerOne researcher [flashmyname](https://hackerone.com/flashmyname).",
  "id": "GHSA-x6mj-8jx9-qhqv",
  "modified": "2026-11-12T23:44:39Z",
  "published": "2026-11-12T23:44:39Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/rails/rails/security/advisories/GHSA-x6mj-8jx9-qhqv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126077"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rails/rails/commit/0e6cf8faa89caf4c64311d35ca2bc88c1458d4e3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rails/rails/commit/849a6c30eacbb6ca4722132f43c4333a93188556"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/rails/rails"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rails/rails/releases/tag/v8.0.5.2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rails/rails/releases/tag/v8.1.4.1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/GHSA-x6mj-8jx9-qhqv.yml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Action Pack: Possible sensitive session information leak in Active Storage proxy mode"
}

CVE-2026-126077 (GCVE-0-2026-126077)

Vulnerability from cvelistv5 – Published: 2026-11-10 20:59 – Updated: 2026-11-10 20:59

Title

Action Pack: Possible sensitive session information leak in Active Storage proxy mode

Summary

Action Pack is a framework for handling and responding to web requests. Prior to 8.1.4.1 and 8.0.5.2, When ActionDispatch::Cookies reads a signed or encrypted cookie that was written under a rotated secret (config.action_dispatch.cookies_rotations) or in the format that a :hybrid cookie serializer migrates from, it writes the cookie back to the response in the current format, and that write ignores request.session_options[:skip]. ActiveStorage::DisableSession relies on that option to keep the session cookie off the public, immutable responses of the Active Storage proxy controllers, but those controllers still load the session, so a request carrying an old-format session cookie could receive the rewritten session cookie in Set-Cookie on a cacheable response. A shared cache that stores such a response together with its Set-Cookie header could then serve one user's session to later requesters of the same URL, or serve an attacker's session to other users. Applications are affected when they serve Active Storage files through the proxy controllers, have a cookie rotation or a :hybrid serializer migration configured, and run behind a cache that stores Set-Cookie on public responses. This is a path around the fix for CVE-2024-26144. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.

Severity

6.8 (Medium)


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

CWE

CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7820 records in the last 180 days details

References

5 references

URL	Tags
https://github.com/rails/rails/security/advisorie…	x_refsource_CONFIRM
https://github.com/rails/rails/commit/0e6cf8faa89…	x_refsource_MISC
https://github.com/rails/rails/commit/849a6c30eac…	x_refsource_MISC
https://github.com/rails/rails/releases/tag/v8.0.5.2	x_refsource_MISC
https://github.com/rails/rails/releases/tag/v8.1.4.1	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
rails	rails	Affected: >= 8.1, < 8.1.4.1 Affected: < 8.0.5.2

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "rails",
          "vendor": "rails",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 8.1, \u003c 8.1.4.1"
            },
            {
              "status": "affected",
              "version": "\u003c 8.0.5.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Action Pack is a framework for handling and responding to web requests. Prior to 8.1.4.1 and 8.0.5.2, When ActionDispatch::Cookies reads a signed or encrypted cookie that was written under a rotated secret (config.action_dispatch.cookies_rotations) or in the format that a :hybrid cookie serializer migrates from, it writes the cookie back to the response in the current format, and that write ignores request.session_options[:skip]. ActiveStorage::DisableSession relies on that option to keep the session cookie off the public, immutable responses of the Active Storage proxy controllers, but those controllers still load the session, so a request carrying an old-format session cookie could receive the rewritten session cookie in Set-Cookie on a cacheable response. A shared cache that stores such a response together with its Set-Cookie header could then serve one user\u0027s session to later requesters of the same URL, or serve an attacker\u0027s session to other users. Applications are affected when they serve Active Storage files through the proxy controllers, have a cookie rotation or a :hybrid serializer migration configured, and run behind a cache that stores Set-Cookie on public responses. This is a path around the fix for CVE-2024-26144. This issue is fixed in versions 8.1.4.1 and 8.0.5.2."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 6.8,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-200",
              "description": "CWE-200: Exposure of Sensitive Information to an Unauthorized Actor",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-10T20:59:00.211Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/rails/rails/security/advisories/GHSA-x6mj-8jx9-qhqv",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/rails/rails/security/advisories/GHSA-x6mj-8jx9-qhqv"
        },
        {
          "name": "https://github.com/rails/rails/commit/0e6cf8faa89caf4c64311d35ca2bc88c1458d4e3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/rails/rails/commit/0e6cf8faa89caf4c64311d35ca2bc88c1458d4e3"
        },
        {
          "name": "https://github.com/rails/rails/commit/849a6c30eacbb6ca4722132f43c4333a93188556",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/rails/rails/commit/849a6c30eacbb6ca4722132f43c4333a93188556"
        },
        {
          "name": "https://github.com/rails/rails/releases/tag/v8.0.5.2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/rails/rails/releases/tag/v8.0.5.2"
        },
        {
          "name": "https://github.com/rails/rails/releases/tag/v8.1.4.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/rails/rails/releases/tag/v8.1.4.1"
        }
      ],
      "source": {
        "advisory": "GHSA-x6mj-8jx9-qhqv",
        "discovery": "UNKNOWN"
      },
      "title": "Action Pack: Possible sensitive session information leak in Active Storage proxy mode"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-126077",
    "datePublished": "2026-11-10T20:59:00.211Z",
    "dateReserved": "2026-11-10T17:07:43.285Z",
    "dateUpdated": "2026-11-10T20:59:00.211Z",
    "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.

Vulnerability timeline

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Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

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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.
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GHSA-X6MJ-8JX9-QHQV

Impact

Details

Workarounds

Releases

Credit

CVE-2026-126077 (GCVE-0-2026-126077)

Tags

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