Jenkins: Reliance on Reverse DNS Resolution for a Security-Critical Action
CVE-2026-33002 is a high-severity reliance on reverse DNS resolution for a security-critical action vulnerability in Jenkins, with a CVSS 3.1 base score of 7.5 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 0.32% 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.
- Read the advisory on jenkins.io for workarounds and exact fixed builds.
- 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
- HighSuccess depends on conditions outside the attacker's control.
- 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:H/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
Jenkins 2.442 through 2.554 (both inclusive), LTS 2.426.3 through LTS 2.541.2 (both inclusive) performs origin validation of requests made through the CLI WebSocket endpoint by computing the expected origin for comparison using the Host or X-Forwarded-Host HTTP request headers, making it vulnerable to DNS rebinding attacks that allow bypassing origin validation.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Reliance on Reverse DNS Resolution for a Security-Critical Action
The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname.
How developers prevent this class of flaw
- Use other means of identity verification that cannot be simply spoofed. Possibilities include a username/password or certificate.
- Perform proper forward and reverse DNS lookups to detect DNS spoofing.
More Reliance on Reverse DNS Resolution for a Security-Critical Action vulnerabilities (CWE-350)
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 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 Reliance on Reverse DNS Resolution for a Security-Critical Action vulnerabilities
- 9.8 Critical severity
- 8.1 High severity
- 8.8 High severity
Spotted an error? Tell us.