CVE-2026-115877
Description
A flaw was found in Twisted. The HTTP server component improperly accepts bare carriage return or line feed characters within header values instead of enforcing strict line endings. A remote attacker can exploit this framing disagreement against an upstream proxy to conduct HTTP request smuggling. This flaw can allow attackers to bypass front-end access controls, poison shared connections or web caches, and expose sensitive responses meant for other clients.
Statement
This vulnerability is rated as Moderate impact because successful exploitation requires an upstream reverse proxy configuration that interprets bare line delimiters differently than the backend Twisted HTTP server. In supported Red Hat environments hosting Twisted services behind proxy intermediaries, an attacker could exploit framing discrepancies to smuggle requests, potentially bypassing proxy access controls or poisoning shared connections. However, the overall severity is bounded because the flaw does not facilitate arbitrary code execution or underlying host compromise.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.4 | N/A | 5.4 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Changed |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
