GHSA-GMJ8-HVJ3-49MW

Vulnerability from github – Published: 2026-11-10 21:25 – Updated: 2026-11-10 21:25
VLAI
Summary
Action Pack: Missing SameSite attribute on session cookies from Action Pack session stores
Details

Impact

Action Pack session stores other than ActionDispatch::Session::CookieStore (CacheStore, MemCacheStore, and third-party stores built on AbstractStore, AbstractSecureStore or the session mixins) write the session cookie without a SameSite attribute, regardless of config.action_dispatch.cookies_same_site_protection, which defaults to :lax. Only CookieStore applies the configured policy. In browsers that do not treat a cookie without the attribute as SameSite=Lax, a cross-site request could carry the session cookie, possibly leading to cross-site request forgery against actions that do not verify an authenticity token, such as those of API-only applications.

Applications are affected when they use a session store other than CookieStore and do not pass same_site: to config.session_store.

Details

In the fixed releases, every session store sets the session cookie's SameSite attribute from cookies_same_site_protection when its options have no :same_site key. An explicit same_site: option, including same_site: nil, and a :same_site value in a store's DEFAULT_OPTIONS still take precedence.

Workarounds

Pass same_site: when configuring the session store, for example config.session_store :cache_store, same_site: :lax.

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/2d9f502df941e31ce9bad0e846564f49396bed46.patch - 8.0: https://github.com/rails/rails/commit/f2392996be723708271a8d30bfcf0edc221e53ef.patch

Credit

This issue was responsibly reported by HackerOne researcher tjvc.

Severity
3.1 (Low)
CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N
Show details on source website
To clipboard 

{
  "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-2026-126067"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-352"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-11-10T21:25:18Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "### Impact\nAction Pack session stores other than `ActionDispatch::Session::CookieStore` (`CacheStore`, `MemCacheStore`, and third-party stores built on `AbstractStore`, `AbstractSecureStore` or the session mixins) write the session cookie without a `SameSite` attribute, regardless of `config.action_dispatch.cookies_same_site_protection`, which defaults to `:lax`. Only `CookieStore` applies the configured policy. In browsers that do not treat a cookie without the attribute as `SameSite=Lax`, a cross-site request could carry the session cookie, possibly leading to cross-site request forgery against actions that do not verify an authenticity token, such as those of API-only applications.\n\nApplications are affected when they use a session store other than `CookieStore` and do not pass `same_site:` to `config.session_store`.\n\n### Details\nIn the fixed releases, every session store sets the session cookie\u0027s `SameSite` attribute from `cookies_same_site_protection` when its options have no `:same_site` key. An explicit `same_site:` option, including `same_site: nil`, and a `:same_site` value in a store\u0027s `DEFAULT_OPTIONS` still take precedence.\n\n### Workarounds\nPass `same_site:` when configuring the session store, for example `config.session_store :cache_store, same_site: :lax`.\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/2d9f502df941e31ce9bad0e846564f49396bed46.patch\n- 8.0: https://github.com/rails/rails/commit/f2392996be723708271a8d30bfcf0edc221e53ef.patch\n\n### Credit\nThis issue was responsibly reported by HackerOne researcher [tjvc](https://hackerone.com/tjvc).",
  "id": "GHSA-gmj8-hvj3-49mw",
  "modified": "2026-11-10T21:25:18Z",
  "published": "2026-11-10T21:25:18Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/rails/rails/security/advisories/GHSA-gmj8-hvj3-49mw"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rails/rails/commit/2d9f502df941e31ce9bad0e846564f49396bed46"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rails/rails/commit/f2392996be723708271a8d30bfcf0edc221e53ef"
    },
    {
      "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-gmj8-hvj3-49mw.yml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Action Pack: Missing SameSite attribute on session cookies from Action Pack session stores"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

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.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    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.