CVE-2026-8023 Path traversal in zephyr
Unauthenticated remote attackers can read arbitrary files on Zephyr RTOS devices by exploiting path traversal in the static-filesystem HTTP handler.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-8023?
CVE-2026-8023 is a high-severity path traversal vulnerability in Zephyrproject Zephyr, published on 29 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-8023?
It affects 1 product.
Products include Zephyrproject Zephyr.
How do I fix CVE-2026-8023?
No fix has been published for CVE-2026-8023 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-8023 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-8023 exists.
Public exploit code: 1 proofs of concept on GitHub.
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- CVE-2018-1000800 Null dereference in n/a
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Sources
Also known as GHSA-hch3-53g6-jj3h.