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CVE.org (no NVD analysis yet)· CNA GitHub_M

CVE-2026-126067: Action Pack: Missing SameSite attribute on session cookies from Action Pack session stores

LowCVSS 3.1 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 12/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.16% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
  • Fixed version: actionpack (RubyGems) 8.1.4.1, 8.0.5.2.

Low priority for now. Upgrade to actionpack (RubyGems) 8.1.4.1, 8.0.5.2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Action Pack is a framework for handling and responding to web requests. Prior to 8.1.4.1 and 8.0.5.2, 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. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.

Published
Nov 10, 2026
Updated
Nov 12, 2026
EPSS
0.1% · 5th percentile

Report tools

JSON

Action score

12

Monitor

Low priority for now.

CVSS
12 / 40 · 3.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · GitHub_M
3.1
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
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  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-126067

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • rails rails

    • >= 8.1, < 8.1.4.1, < 8.0.5.2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12railsfrom 0—
RubyGemsactionpackfrom 8.1.0.beta1 · before 8.1.4.18.1.4.1
RubyGemsactionpackbefore 8.0.5.28.0.5.2

Same product

rails: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-66066Action Pack: Possible arbitrary file read and remote code execution in Active Storage variant processing
    60This week
  • CVE-2026-126186Active Storage: Possible arbitrary file read and remote code execution in Active Storage video previews, analysis and image processing
    35Monitor
  • CVE-2026-126081Action Pack: Possible Strong Parameters bypass in Parameters#each_key
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2024-54133Dec 10, 2024 · Possible Content Security Policy bypass in Action Dispatch
    9Monitor
  • ← EarlierCVE-2025-55193Aug 13, 2025 · Active Record logging vulnerable to ANSI escape injection
    10Monitor
  • Later →CVE-2026-126068Nov 10, 2026 · Action Mailbox: Possible signature replay in Action Mailbox Mailgun ingress
    14Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
RubyGems:actionpack8.0.5.2Package registry (OSV)
RubyGems:actionpack8.1.4.1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 13, 2026+3 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Not on record for this CVE: researcher credit · variant or chain candidate.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-352 · Cross-Site Request Forgery (CSRF)

CVSS vector

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

nvd-secondary

Root cause

State-changing requests rely on the session cookie the browser sends automatically; nothing verifies that the request came from the user’s own page.

The bug in code

The whole CWE-352 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
app.use(session({ cookie: { httpOnly: true } }));app.post("/account/address", updateAddress);

Fixed

ts
app.use(session({ cookie: { httpOnly: true, sameSite: "lax" } }));app.post("/account/address", csrfProtection, updateAddress);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records