Dashboard / CVE-2026-71554

CVE-2026-71554

MEDIUM
MEDIUM Priority: 0.02 BB Relevance: 71/100
Published: 2026-08-06 Modified: 2026-10-24 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
S: Unchanged
C: None
I: None
A: Low

Description

h2 is a pure-Python implementation of a HTTP/2 protocol stack. Versions up to and including 4.4.0 accept request header blocks containing more than one Host header, and forward every Host header to the consuming application. Where the consumer downgrades HTTP/2 to HTTP/1.1, the resulting request carries two Host header lines, providing a request smuggling primitive. This issue is fixed in version 4.4.1.

Weakness Classification (1)

References & Advisories (2)

Bug Bounty Relevance

71 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

CVSS Score

5.3 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS — Exploitation Probability

0.42%
Raw Score 0.004180
Percentile 36.1%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00418
2026-10-28
0.00418

Intelligence Sources

nvd ref →

External Links