CVE-2026-109829
Description
A flaw was found in undici. When an application configures redirect handling alongside a shared cache, responses received after cross-origin redirects are incorrectly stored under the initial request URL. A remote attacker who controls a redirect destination can exploit this vulnerability to poison the shared cache, serving malicious content to subsequent users requesting trusted URLs. Additionally, this behavior can result in information disclosure if private or user-specific responses are cached and delivered to unauthorized callers.
Statement
This vulnerability is rated as Important severity because successful exploitation enables remote attackers to achieve shared cache poisoning and unauthorized cross-user data exposure across network boundaries without requiring elevated privileges. Within Red Hat environments shipping Node.js runtimes and associated container services, undici is utilized as an HTTP client backend. However, exploitation requires a specific application architecture where an originless dispatcher chains redirect processing ahead of a shared cache store, rather than the default standalone client configurations. Deployments that do not implement shared caching across multi-origin redirect flows or that isolate cache storage per origin remain unaffected by this flaw.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.4 | 9.1 | 7.4 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | Low | High |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Understanding the Weakness (CWE)
Access Control,Other
Technical Impact: Gain Privileges or Assume Identity; Varies by Context
An attacker can access any functionality that is inadvertently accessible to the source.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
