EEF-CVE-2026-66885 CVE-2026-66885 GHSA-pvvw-28fw-c6fg
Livebook Teams identity callback lacks state binding, allowing login CSRF
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.24%
- Chance of exploitation in the next 30 days. Higher than 14.43% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-352 Cross-Site Request Forgery (CSRF)
- Fix
0.19.9- Upgrade livebook to this version or later
Description
Summary
Cross-Site Request Forgery (CSRF) vulnerability in livebook-dev livebook allows an attacker to authenticate a victim's browser session under the attacker's own Livebook Teams identity.
When Livebook is configured to use Livebook Teams for identity, Livebook.ZTA.LivebookTeams.handle_request/4 in lib/livebook/zta/livebook_teams.ex handles the OAuth-style callback carrying a teams_identity marker and a code parameter. The clause exchanges that code for an access token and writes the token into the browser session without verifying any value that ties the callback to the browser session that started the login. No state or nonce is generated when the flow is initiated: Livebook.Teams.Requests.create_auth_request/1 in lib/livebook/teams/requests.ex sends an empty request body, so no per-attempt value is ever registered, and the callback clause has nothing to compare against.
An attacker who holds membership in the same Livebook Teams organisation as the target instance can therefore begin the login flow themselves, retain the resulting authorization code without redeeming it, and induce a victim to open a crafted URL carrying that code. The victim's browser completes the exchange and the resulting session is bound to the attacker's identity rather than the victim's. The victim is not required to hold any particular privilege, and no credential belonging to the victim is involved. The vulnerability does not allow the attacker to authenticate as the victim.
The consequence is that a user believes they are working in their own authenticated session while they are in fact operating as another identity. Work performed in that session is attributed to the attacker's account, and secrets, uploaded data, or notebook results the victim produces are exposed to the attacker rather than kept in the victim's own account. The authorization code must be redeemed within a short window after the login flow begins, which constrains the timing of the attack but not its feasibility.
This issue affects livebook: from 0.15.0 before 0.18.7 and from 0.19.0 before 0.19.9.
Affected versions
Hex
| Package | Vulnerable | Fixed in |
|---|---|---|
| livebook | >= 0.15.0, < 0.18.7>= 0.19.0, < 0.19.9 |
0.18.70.19.9 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
livebook Hex → 0.19.9
- mix
{:livebook, "~> 0.19.9"} # then: mix deps.update livebook
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- Low
- User interaction
- Active
- Confidentiality (vulnerable system)
- High
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Weakness
CWE-352: Cross-Site Request Forgery (CSRF)
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.
How to prevent it
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482]. For example, use anti-CSRF packages such as the OWASP CSRFGuard. [REF-330] Another example is the ESAPI Session Management control, which includes a component for CSRF. [REF-45]
- Implementation: Ensure that the application is free of cross-site scripting issues (CWE-79), because most CSRF defenses can be bypassed using attacker-controlled script.
- Architecture and Design: Generate a unique nonce for each form, place the nonce into the form, and verify the nonce upon receipt of the form. Be sure that the nonce is not predictable (CWE-330). [REF-332]
- Architecture and Design: Identify especially dangerous operations. When the user performs a dangerous operation, send a separate confirmation request to ensure that the user intended to perform that operation.
- Architecture and Design: Use the "double-submitted cookie" method as described by Felten and Zeller: When a user visits a site, the site should generate a pseudorandom value and set it as a cookie on the user's machine. The site should require every form submission to include this value as a form value and also as a cookie value. When a POST request is sent to the site, the request should only be considered valid if the form value and the cookie value are the same. Because of the same-origin policy, an attacker cannot read or modify the value stored in the cookie. To successfully submit a form on behalf of the user, the attacker would have to correctly guess the pseudorandom value. If the pseudorandom value is cryptographically strong, this will be prohibitively difficult. This technique requires Javascript, so it may not work for browsers that have Javascript disabled. [REF-331]
- Architecture and Design: Do not use the GET method for any request that triggers a state change.
- Implementation: Check the HTTP Referer header to see if the request originated from an expected page. This could break legitimate functionality, because users or proxies may have disabled sending the Referer for privacy reasons.
References
Advisories
Fixes and patches
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| EEF-CVE-2026-66298 JS-view sandboxed output can synthesize keyboard events to trigger unconfirmed global shortcuts | High | Also affects livebook |
| EEF-CVE-2026-66297 Unescaped deployment environment variables in generated setup commands | High | Also affects livebook |
| EEF-CVE-2026-66881 Path traversal in imported file_entries name allows arbitrary file write via URL-type entry download | High | Also affects livebook |
| EEF-CVE-2026-68746 Livebook Teams identity check fails open when the deployment group is unresolvable, allowing unauthenticated access | High | Also affects livebook |
| GHSA-564w-97r7-c6p9 Livebook Desktop's protocol handler can be exploited to execute arbitrary command on Windows | Critical | Also affects livebook |
| GHSA-2p8c-gr87-2676 Electron: SameSite cookie restrictions are not applied to windows opened from links | Medium | Same weakness, CWE-352 |
| GO-2026-6773 Nginx UI: Casdoor SSO callback uses a constant `state` parameter (login CSRF) | High | Same weakness, CWE-352 |
| GHSA-9ff2-p842-45wq Contao: Cross-site request forgery in custom backend actions | Low | Same weakness, CWE-352 |
Credits: Hugo Baraúna, Jonatan Kłosko, José Valim, Nguyễn Công Tú
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