CVE-2026-55484

Received Received - Intake

Out-of-Bounds Panic in ALOS HTTP Framework

Publication date: 2026-08-28

Last updated on: 2026-08-28

Assigner: GitHub, Inc.

Description

ALOS HTTP is a Linux-first Go web framework and application server built around a custom networking stack. Prior to 0.0.0-20260617230736-314b6783e196, core/utils.go::sanitizeRequestPath calls splitPathQuery on a request path beginning with a question mark and then performs the unchecked p[0] access without checking whether the resulting path is empty. An unauthenticated client can send a malformed request such as a question-mark-only path through h1_plain.go::ParseH1RequestHead, hpack.go::decodeSimpleGetPathHTTPSRequest, hpack.go::observeHeader, or h3_conn.go::handleRequestStream, causing an out-of-bounds panic before core.Recovery() middleware runs and terminating the server process. This issue is fixed in pseudo-version 0.0.0-20260617230736-314b6783e196.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-28

Last Modified

2026-08-28

Generated

2026-08-29

AI Q&A

2026-08-29

EPSS Evaluated

N/A

NVD

CVE-2026-55484

EUVD

EUVD-2026-67872

Affected Vendors & Products

Vendor	Product	Version / Range
guno1928	alos-http	to 0.0.0-20260617230736-314b6783e196 (exc)
guno1928	alos-http	314b678

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-754	The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.
CWE-248	An exception is thrown from a function, but it is not caught.

Attack-Flow Graph

Executive Summary

CVE-2026-55484 is a high-severity unauthenticated remote denial-of-service (DoS) vulnerability in the ALOS HTTP Go framework. It occurs when a malformed HTTP request with a path starting with a question mark (?) is processed. The server's sanitizeRequestPath function fails to handle this case, causing an out-of-bounds panic that crashes the entire server process before any recovery mechanisms can act.

Detection Guidance

Monitor server logs for crashes or panics triggered by HTTP requests with paths starting with a question mark (e.g., GET /? or GET ?). Use network traffic analysis tools like tcpdump or Wireshark to inspect incoming requests for malformed paths. Check for unexpected server terminations or dropped connections during load testing with tools like ab or wrk.

Impact Analysis

This vulnerability allows an unauthenticated attacker to send a single malicious request that crashes the server, terminating all active connections. It affects availability by causing downtime and requires no privileges or user interaction to exploit. The attack impacts HTTP/1.1, HTTP/2, and HTTP/3 (if QUIC is enabled).

Mitigation Strategies

Deploy a reverse proxy (e.g., Nginx, Apache) in front of the ALOS HTTP server to filter malicious requests before they reach the vulnerable application. Update to the patched version if available. Restrict network access to the server using firewalls or allowlists. Monitor and rate-limit incoming requests to prevent abuse.

Hi! I’m here to help you understand CVE-2026-55484. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70