CVE-2026-126067VulnerabilityPublished 12 Nov 2026Updated 13 Nov 2026

Rails: Prior to 8.1.4.1 and 8.0.5.2, Action Pack session stores other than ActionDispatch::Session::CookieStore

Affects railsSource GCVE Database

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Authoritative record:CVE-2026-126067· Low 3.1

Not known to be exploited · CVSS 3.1 Low · fixed in 8.1.4.1 : update rails when convenient.

Data as of 13 Nov 2026, 22:32 UTC

CVSS 3.1 base score

3.1Low

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	3.1

Patch: Available – fixed in 8.1.4.1

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.10rails`pkg:deb/ubuntu/rails?arch=source&distro=stonking`Other threats	Affected =2:7.2.3+dfsg-2 =2:7.2.3.2+dfsg-2	Fixed in–
Ubuntu 26.04 LTSrails`pkg:deb/ubuntu/rails?arch=source&distro=resolute`Other threats	Affected =2:7.2.2.1+dfsg-7 =2:7.2.2.2+dfsg-2 =2:7.2.3+dfsg-2	Fixed in–
Ubuntu 24.04 LTSrails`pkg:deb/ubuntu/rails?arch=source&distro=noble`Other threats	Affected =2:6.1.7.3+dfsg-2build1 =2:6.1.7.3+dfsg-3	Fixed in–
Ubuntu Pro 22.04 LTSrails`pkg:deb/ubuntu/rails?arch=source&distro=esm-apps/jammy`Other threats	Affected =2:6.0.3.7+dfsg-2 =2:6.1.4.1+dfsg-8ubuntu2 =2:6.1.4.1+dfsg-8ubuntu2+esm1	Fixed in–
Ubuntu Pro 20.04 LTSrails`pkg:deb/ubuntu/rails?arch=source&distro=esm-apps/focal`Other threats	Affected =2:5.2.2.1+dfsg-1ubuntu1 =2:5.2.3+dfsg-3 =2:5.2.3+dfsg-3ubuntu0.1~esm1	Fixed in–
Ubuntu Pro 18.04 LTSrails`pkg:deb/ubuntu/rails?arch=source&distro=esm-apps/bionic`Other threats	Affected 2:4.2.9-2 – 2:4.2.10-0ubuntu4+esm2 5 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Rails to version 8.1.4.1 or 8.0.5.2 or later, where this issue is fixed. Alternatively, ensure that applications using session stores other than CookieStore explicitly set the same_site option in config.session_store to enforce the desired SameSite cookie policy. No other immediate actions are required if the application uses CookieStore or already configures same_site correctly.

Description

Prior to versions 8.1.4.1 and 8.0.5.2 of Rails, Action Pack session stores other than the default CookieStore do not set the SameSite attribute on session cookies. This omission can cause browsers that do not default to SameSite=Lax to send session cookies on cross-site requests, potentially enabling cross-site request forgery (CSRF) attacks against actions lacking authenticity token verification, such as API-only application endpoints. The issue affects applications using session stores like CacheStore, MemCacheStore, or third-party stores without explicitly configuring the same_site option. The vulnerability is fixed in Rails versions 8.1.4.1 and 8.0.5.2.

Impact

The vulnerability can lead to cross-site request forgery (CSRF) attacks in affected Rails applications that use session stores other than CookieStore and do not explicitly set the same_site option. This can allow an attacker to perform unauthorized actions on behalf of an authenticated user in browsers that do not default missing SameSite cookies to Lax. The impact is limited to applications that do not verify authenticity tokens on sensitive actions, such as API-only applications. The CVSS score is low (3.1) reflecting the limited attack vector and required conditions.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Nov 2026, 22:32 UTC

Technical details

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