GHSA-gmj8-hvj3-49mw

Action Pack: Missing SameSite attribute on session cookies from Action Pack session stores

Products / packages rails · actionpack

Published 10/11/2026, 20:29:44 UTC

Severity and exploitation

Not in CISA KEVSource: LOW

KEV coverage does not rule out exploitation.

KEV checked 15/11/2026, 01:10:30 UTC

OSV · CVSS:3.0 · 3.1

Assessment vector

CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N

GitHub_M · CVSS:3.1 · 3.1

Assessment vector

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

The headline uses the highest imported catalog score. Assessments can differ by source and CVSS version.

Severity

low3.1

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Package fixes recorded

Fix versions are recorded for 1 of 1 mapped packages. Check each release branch and any separate product guidance.

What this means

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…

Source excerpt · OSV

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

rails · GitHub_M

rails

2 ranges

GitHub_M version evidence

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

>= 8.1, < 8.1.4.1

< 8.0.5.2

Other versions: unknown

Packages

Compare each installed version with the publisher’s affected ranges. Where a fix is recorded, choose the appropriate release branch and test compatibility before upgrading.

actionpack RubyGems

Affected range	Recorded fix
From 8.1.0.beta1 before 8.1.4.1Ecosystem versions	8.1.4.1
Earlier releases before 8.0.5.2Ecosystem versions	8.0.5.2

Version evidence: OSV · GHSA-gmj8-hvj3-49mw

View original version evidence (520 explicit versions)

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

Use the recorded fix for your release branch. Review the publisher’s instructions and test compatibility before upgrading.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

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:

Credit

This issue was responsibly reported by HackerOne researcher tjvc.

References

7 sources

rails/rails · security/advisories/GHSA-gmj8-hvj3-49mw

Security advisoryGitHub_M

rails/rails · commit 2d9f502

PatchGitHub_M

rails/rails · commit f239299

PatchGitHub_M

rails/rails · repository

Source reference

rails/rails · releases/tag/v8.0.5.2

Release notesGitHub_M

rails/rails · releases/tag/v8.1.4.1

Release notesGitHub_M

View 1 more references

rubysec/ruby-advisory-db · GHSA-gmj8-hvj3-49mw.yml

Source reference

Inside the record

Evidence available

Package identity

Version evidence

Remediation guidance · not supplied

Weakness classification

Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-126067

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-352 ↗

CWE-352: Cross-Site Request Forgery

GitHub_M

Contributing organizations · 2

GitHub_M

Assigning organization

2026-11-10

CISA-ADP

Additional data publisher

2026-11-13

Timeline

All times UTC

10 Nov 2026, 20:29
Advisory published
Publication date supplied by the source.
13 Nov 2026, 16:00
Source updated
Latest modification date supplied by the source.
13 Nov 2026, 23:25
Last imported by cve.new
Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes

CVE · CVE-2026-1260672026-11-13

Observed 2026-11-13T23:25:59.268Z · upstream updated 2026-11-13T16:00:26.328Z

Prioritization updated

before

[]

after

[
  {
    "source": "CISA-ADP",
    "type": "SSVC",
    "role": "CISA Coordinator",
    "timestamp": "2026-11-13T15:56:36.588222Z",
    "decisions": [
      {
        "name": "Exploitation",
        "value": "none"
      },
      {
        "name": "Automatable",
        "value": "no"
      },
      {
        "name": "Technical Impact",
        "value": "partial"
      }
    ]
  }
]

Large field values are marked as truncated previews. Original source snapshots remain retained.

Showing up to 50 most recent observed changes.

Reading the signals

Severity · CVSS: Technical impact and attack conditions. The headline is the highest imported catalog score; sources may disagree.
Observed exploitation · KEV: An absent or unavailable KEV listing does not establish that exploitation has not occurred.
Predicted exploitation · EPSS: No EPSS estimate available in this record.

CISA-ADP · SSVC

CISA Coordinator · 2026-11-13

Exploitation: none
Automatable: no
Technical Impact: partial

SSVC describes the publisher’s decision context. Your organization’s exposure and priorities may differ.

Record identifiers

Aliases: CVE-2026-126067

Source evidence

Request a correction or dispute

Start with the assigning organization for this record. Include the CVE ID, the disputed information, and supporting evidence. A dispute does not itself reject a record.

Find the responsible CNA →Official dispute and escalation process ↗

OSV GHSA-gmj8-hvj3-49mw CVE CVE-2026-126067