CVE-2026-84649
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.
What this means for your business
- An attacker can use it remotely, over a network, without a login, but only after tricking someone into an action such as opening a file or a link.
- FIRST's prediction model gives it a 0.2% chance of attack attempts being seen in the next 30 days, ranking above 8% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Fastnexa security experts
Not sure if your company is exposed to CVE-2026-84649?
Tell us where you run the affected software and a Fastnexa penetration tester will check whether this flaw, or others like it, can be used against your websites, apps and network.
The full test is free for our first 10 founding clients until 31 December 2026. See the offer
Think you’ve already been hit? Don’t wait on a form: call or WhatsApp +1 (732) 454 2616. We reply within 1 hour, 24/7. Emergency help →
Scoring
- CVSS
- 8.8 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H- Weakness
- CWE-352
- Assigned by
- jenkinsci-cert@googlegroups.com
Dates
- Published
- 2026-09-02
- Last modified
- 2026-09-03
- Sources
- NVD