OpenLiteSpeed through 1.9.4 mTLS Bypass via HTTP/3 SNI and Host Mismatch

OpenLiteSpeed through 1.9.4 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to evade virtual host client certificate requirements over HTTP/3. Because QuicStream inherits a verifyContext() implementation that always returns true, attackers can present a non-mTLS host's SNI with a protected Host header to access protected content.

LiteSpeed Cache <= 7.9.1 - Unauthenticated Sensitive Information Disclosure (WooCommerce Store API Cart/Checkout PII + Cart-Token) via Public REST Caching

The LiteSpeed Cache plugin for WordPress is vulnerable to unauthenticated disclosure of sensitive WooCommerce customer data in all versions up to, and including, 7.9.1 With Cache REST enabled (the shipped default cache-rest=1), LiteSpeed stores WooCommerce Store API GET responses (/wc/store/v1/cart and /wc/store/v1/checkout) as PUBLIC cache objects and does not vary the cache on the Cart-Token or WooCommerce session. A shopper's personalized cart/checkout response is therefore served to any later, cookie-less and token-less client as an LSCache HIT. This makes it possible for unauthenticated attackers to read another shopper's billing and shipping details (name, company, street address, email, phone), cart contents and totals, and the shopper's live Cart-Token session JWT and nonce (enabling cart/checkout-session hijack), plus order_key on the checkout endpoint.

LiteSpeed Web Server (LSWS) before 6.3.7 build 1 mishandles internal redirect URL validation in a certain "corner case" of %252e%252e double decoding, letting a low-privileged tenant execute code in the context of a different account.

LiteSpeed Cache <= 7.9.1 - Authenticated (Subscriber+) Stored Cross-Site Scripting via VPI Image Attribute Re-Serialization

The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'bbp_reply_content' parameter in all versions up to, and including, 7.9.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Exploitation requires that an administrator has enabled Viewport Images (VPI) and configured a VPI filename that matches an image the attacker can embed in user-generated content — such as a bbPress topic where Subscriber-level Participants are permitted to post replies containing raw img tags.

LiteSpeed Cache <= 7.9.1 - Unauthenticated Stored Cross-Site Scripting via HTML Minifier Predictable Placeholder (md5(REQUEST_TIME) + two-pass str_replace)

The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'comment' parameter in all versions up to, and including, 7.9.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This vulnerability is only exploitable when the HTML Minify option (O_OPTM_HTML_MIN) is enabled and a companion plugin renders stored comment content into a raw-text context such as a JSON-LD script block on the same page.

Privilege Escalation in LiteSpeed cPanel Plugin via Improper Redis Handling

LiteSpeed User-End cPanel Plugin before 2.4.5 allows privilege escalation (possibly to root), as exploited in the wild in May 2026. Detection is best done via a command line of grep -rE "cpanel_jsonapi_func=redisAble" /var/cpanel/logs /usr/local/cpanel/logs/ 2>/dev/null in Bash. If you get no output, you have not been hit with exploitation of the vulnerability. If there is output, we recommend you examine the IP addresses in the list, determine if they are valid IP addresses, and if not, block them. To determine damage done, examine the system logs for use by the detected IP addresses. The issue is related to mishandling of Redis enable/disable features. The recommended minimum version is 2.4.7.

Unbounded Header Buffers in LiteSpeed HTTP/3 Allow Memory Exhaustion via QPACK Amplification

In lsquic before 4.9.0, the HTTP/3 implementation can use an excessive amount of memory because the number of buffered header sets is not limited, as demonstrated by a QPACK amplification attack. This is related to header_out_dynamic_entry and es_max_header_list_size.

OpenLiteSpeed before 1.9.3 Local Privilege Escalation via lsup.sh Auto-Update

OpenLiteSpeed before 1.9.3 contains a local privilege escalation vulnerability in admin/misc/lsup.sh that runs unverified update packages from a nobody-writable directory as root. Attackers controlling the nobody web process can replace the package in /usr/local/lsws/autoupdate/ before extraction, so its install.sh runs as root on the next update.

LiteSpeed Cache <= 7.9 - Reflected Cross-Site Scripting via ESI 'esi' Parameter

The LiteSpeed Cache plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'esi' parameter in all versions up to, and including, 7.9 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. Exploitation requires that the attacker supply a validly signed 'esi' value in the GET query string while submitting a separate attacker-controlled 'esi' payload as a POST body field, relying on PHP's default $_REQUEST merge order to have the POST value take precedence at the point of execution.

LiteSpeed Cache <= 7.7 - Authenticated (Author+) Stored Cross-Site Scripting via img Tag Attributes

The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via crafted `<img>` tag attributes in all versions up to, and including, 7.7. This is due to a flawed regular expression that is used to strip `width` and `height` attributes from images when the "Lazy Load Images" and "Add Missing Sizes" features are enabled. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that execute whenever a user accesses an injected page.

LiteSpeed Cache <= 7.8.1 - Unauthenticated Stored Cross-Site Scripting via Comment Content

The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content in all versions up to, and including, 7.8.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. A comment payload crafted exclusively from decimal numeric character references (e.g. &#34;, &#60;, &#62;) placed inside an allowed element such as &lt;code&gt; bypasses WordPress's wp_kses sanitization, as kses does not treat a data-settings="..." substring within text content as an HTML attribute, allowing the malicious payload to reach the vulnerable function. For this to be exploitable, the site must allow users with previously approved comments to write new comments, and the require_name_email setting must be disabled.

LiteSpeed Web Server Enterprise 5.4.11 - Command Injection

LiteSpeed Web Server Enterprise 5.4.11 contains an authenticated command injection vulnerability in the external app configuration interface. Authenticated administrators can inject shell commands through the 'Command' parameter in the server configuration, allowing remote code execution via path traversal and bash command injection.

OpenLiteSpeed and LSWS Enterprise provided by LiteSpeed Technologies contain an OS command injection vulnerability. An arbitrary OS command may be executed by an attacker with the administrative privilege.

Symbolic Link Path Traversal in LiteSpeed cPanel Plugin Allows Remote Code Execution

LiteSpeed cPanel plugin before 2.4.8 (as distributed in LiteSpeed WHM PlugIn before 5.3.2.0) mishandles symlinks provided by a user with FTP or web shell access on a shared hosting server running CloudLinux/CageFS, as exploited in the wild in May 2026.

A hash collision vulnerability (in the hash table used to manage connections) in LSQUIC (aka LiteSpeed QUIC) before 4.2.0 allows remote attackers to cause a considerable CPU load on the server (a Hash DoS attack) by initiating connections with colliding Source Connection IDs (SCIDs). This is caused by XXH32 usage.

LiteSpeed Cache <= 7.7 - Unauthenticated Stored Cross-Site Scripting via QUIC.cloud CCSS/UCSS REST API Endpoints

The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the /wp-json/litespeed/v1/notify_ccss and /wp-json/litespeed/v1/notify_ucss REST API endpoints in all versions up to, and including, 7.7. These endpoints accept CSS content from QUIC.cloud callback notifications and store it to disk without sanitization. The stored content is later rendered inline frontend page loads without output escaping. The access control protecting these endpoints is IP-based validation that can potentially be bypassed when the WordPress site is deployed behind a reverse proxy, load balancer, or CDN with certain configurations. This makes it possible for unauthenticated attackers, under certain conditions, to inject arbitrary JavaScript into CCSS/UCSS content.

WordPress LiteSpeed Cache plugin <= 5.7 - Unauthenticated Broken Access Control on API vulnerability

Missing Authorization vulnerability in LiteSpeed Technologies LiteSpeed Cache.This issue affects LiteSpeed Cache: from n/a through 5.7.

WordPress LiteSpeed Cache plugin <= 5.7 - Unauthenticated Site Wide Stored XSS vulnerability

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in LiteSpeed Technologies LiteSpeed Cache allows Stored XSS.This issue affects LiteSpeed Cache: from n/a through 5.7.

WordPress LiteSpeed Cache plugin <= 6.5.1 - Privilege Escalation vulnerability

Incorrect Privilege Assignment vulnerability in LiteSpeed Technologies LiteSpeed Cache litespeed-cache allows Privilege Escalation.This issue affects LiteSpeed Cache: from n/a through <= 6.5.1.

WordPress LiteSpeed Cache plugin <= 6.4.1 - Path Traversal vulnerability

Relative Path Traversal vulnerability in LiteSpeed Technologies LiteSpeed Cache litespeed-cache allows Path Traversal.This issue affects LiteSpeed Cache: from n/a through <= 6.4.1.