CVE Catalog

CVE-2026-8023

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Elevated risk
0.91%

56th percentile - higher than 56% of all known CVEs

Summary

The HTTP server in Zephyr (subsys/net/lib/http) is vulnerable to path traversal in the static filesystem resource handler (HTTP_RESOURCE_TYPE_STATIC_FS). An attacker can send a GET request with ../ sequences in the URL path to read arbitrary files outside the configured root directory. Affects versions v4.0.0 through v4.4.0 when file system support (CONFIG_FILE_SYSTEM) is enabled.

Risk Assessment

An unauthenticated remote attacker can read arbitrary readable files on the mounted volume, leading to disclosure of sensitive organizational data such as configurations, keys, or user data.

Recommendation

Immediately update Zephyr to a patched version (v4.4.1 or later) or apply the fix manually. If updating is not possible, temporarily disable the static filesystem resource (HTTP_RESOURCE_TYPE_STATIC_FS) or restrict access to the HTTP server via firewall.

Related vulnerabilities

Original NVD description (English source)

Zephyr's HTTP server (subsys/net/lib/http) provides a static-filesystem resource type (HTTP_RESOURCE_TYPE_STATIC_FS, available when CONFIG_FILE_SYSTEM is enabled) that serves files from a configured root directory. Before this fix, both the HTTP/1 and HTTP/2 front-ends placed the raw, attacker-controlled request path into client->url_buffer (assembled in on_url() for HTTP/1 and copied verbatim from the :path pseudo-header for HTTP/2) without resolving ./.. segments. The static-FS handler then built the on-disk filename by directly concatenating the configured root with that raw URL (snprintk(fname, ..., "%s%s", static_fs_detail->fs_path, client->url_buffer) at http_server_http1.c:603 and http_server_http2.c:490) and opened it with fs_open(fname, FS_O_READ). Because the handler is reached via wildcard/leading-dir (fnmatch FNM_LEADING_DIR) or fallback resource matching, a request such as GET /<prefix>/../../<file> is dispatched to the handler and, after the underlying filesystem (e.g. LittleFS/FAT) resolves the .. segments, escapes the configured web root, letting an unauthenticated remote client read arbitrary readable files on the mounted volume (information disclosure). The HTTP server requires no TLS or authentication to reach this path. The fix adds http_server_remove_dot_segments(), which canonicalizes the path portion of the URL before resource lookup in both protocol handlers, neutralizing the traversal. Affects releases v4.0.0 through v4.4.0 for deployments that register a static-filesystem resource.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS