Jenkins: Cross-Site Request Forgery
CVE-2026-84649 is a high-severity cross-site request forgery vulnerability in Jenkins, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. There is no confirmed exploitation so far. EPSS estimates a 0.2% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Jenkins you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Jenkins Project | Jenkins | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
In Stapler 1839.ved17667b_a_eb_5 through 2107.v8dfcb_e8ed317 (both inclusive), except 2088.2093.vd7c3e58008a_6, included in Jenkins 2.447 through 2.579 (both inclusive), LTS 2.452.1 through 2.568.2 (both inclusive), an HTTP endpoint serving dynamically generated JavaScript resources embeds the user's cross-site request forgery (CSRF) token (crumb) as a string literal, allowing attackers with control over a page hosted on the same site as Jenkins to obtain a valid crumb for the targeted user's session and perform actions on their behalf.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Cross-Site Request Forgery
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 developers prevent this class of flaw
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, use anti-CSRF packages such as the OWASP CSRFGuard. Another example is the ESAPI Session Management control, which includes a component for CSRF.
- Ensure that the application is free of cross-site scripting issues (CWE-79), because most CSRF defenses can be bypassed using attacker-controlled script.
- 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).
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Jenkins
- 8.8 High severity
- 8.8 High severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
- 8.8 High severity
Recent Cross-Site Request Forgery vulnerabilities
- 8.3 High severity
- 7.4 High severity
- 7.1 High severity
- 8.1 High severity
- 7.5 High severity
- 8.4 High severity
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