CVE-2026-8023: info-leak in zephyrproject zephyr
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.
AI Analysis
Technical Summary
The Zephyr project’s HTTP server static-filesystem resource (enabled with CONFIG_FILE_SYSTEM) concatenates the raw, attacker-controlled URL path directly with the configured root directory without resolving dot-segments (./ and ../). This allows directory traversal by sending crafted requests with ../ sequences, escaping the intended web root and reading arbitrary files on the mounted filesystem. Both HTTP/1 and HTTP/2 handlers are affected. The vulnerability affects Zephyr releases from v4.0.0 through v4.4.0 for deployments using the static filesystem resource. The fix involves adding a path canonicalization function (http_server_remove_dot_segments()) to sanitize the URL path before file lookup, preventing traversal.
Potential Impact
An unauthenticated remote attacker can exploit this vulnerability to read arbitrary files on the device's mounted filesystem that are outside the intended web root directory. This leads to information disclosure of potentially sensitive data. The vulnerability does not affect integrity or availability, only confidentiality. No authentication or TLS is required to reach the vulnerable code path.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The vendor has introduced a fix that canonicalizes URL paths to prevent directory traversal. Until a patch is applied, avoid enabling the static-filesystem resource or restrict access to the HTTP server. Monitor vendor channels for official patches or updates.
CVE-2026-8023: info-leak in zephyrproject zephyr
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.
CVSS v3.1
Score 7.5high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Zephyr project’s HTTP server static-filesystem resource (enabled with CONFIG_FILE_SYSTEM) concatenates the raw, attacker-controlled URL path directly with the configured root directory without resolving dot-segments (./ and ../). This allows directory traversal by sending crafted requests with ../ sequences, escaping the intended web root and reading arbitrary files on the mounted filesystem. Both HTTP/1 and HTTP/2 handlers are affected. The vulnerability affects Zephyr releases from v4.0.0 through v4.4.0 for deployments using the static filesystem resource. The fix involves adding a path canonicalization function (http_server_remove_dot_segments()) to sanitize the URL path before file lookup, preventing traversal.
Potential Impact
An unauthenticated remote attacker can exploit this vulnerability to read arbitrary files on the device's mounted filesystem that are outside the intended web root directory. This leads to information disclosure of potentially sensitive data. The vulnerability does not affect integrity or availability, only confidentiality. No authentication or TLS is required to reach the vulnerable code path.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The vendor has introduced a fix that canonicalizes URL paths to prevent directory traversal. Until a patch is applied, avoid enabling the static-filesystem resource or restrict access to the HTTP server. Monitor vendor channels for official patches or updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- zephyr
- Date Reserved
- 2026-05-05T23:01:35.471Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a42f37c27e9c797199f7590
Added to database: 06/29/2026, 22:36:44 UTC
Last enriched: 07/22/2026, 22:52:21 UTC
Last updated: 08/13/2026, 12:41:11 UTC
Views: 217
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