spacetime Ad Inserter Plugin up to 2.8.18 on WordPress replace_ai_tags HTTP_REFERER cross site scripting

Summaryinfo

A vulnerability labeled as problematic has been found in spacetime Ad Inserter Plugin up to 2.8.18. This impacts the function replace_ai_tags. Such manipulation of the argument HTTP_REFERER leads to cross site scripting. This vulnerability is referenced as CVE-2026-19902. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in spacetime Ad Inserter Plugin up to 2.8.18 and classified as problematic. Affected by this issue is the function replace_ai_tags. The manipulation of the argument HTTP_REFERER with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. CVE summarizes:

The Ad Inserter – Ad Manager & AdSense Ads plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the Referer header in all versions up to, and including, 2.8.18 due to insufficient input sanitization and output escaping on the '{search-query}' dynamic tag. When an ad block's code contains that tag, replace_ai_tags() reads $_SERVER['HTTP_REFERER'] and tests it with the regex /[\.\/](google|yahoo|bing|ask)\.[a-z\.]{2,5}[\/]/i. The leading [\.\/] class matches a literal slash, so any referrer merely containing a segment such as '/google.com/' passes as a search-engine referral; the plugin then percent-decodes the referring query with parse_str() and substitutes the resulting 'q' (or 'p') value into the block via preg_replace() with no escaping. This makes it possible for unauthenticated attackers to execute arbitrary JavaScript in the context of the site for any visitor, including a signed-in administrator, by luring them to an attacker-controlled page that frames or links to any ordinary post. Exploitation requires the site to have an ad block whose code uses the '{search-query}' tag with automatic insertion enabled — a documented plugin feature used as intended.

The advisory is shared for download at wordfence.com. This vulnerability is handled as CVE-2026-19902 since 08/14/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• WordPress Plugin

Vendor

• spacetime

Name

• Ad Inserter Plugin

Version

• 2.8.0
• 2.8.1
• 2.8.2
• 2.8.3
• 2.8.4
• 2.8.5
• 2.8.6
• 2.8.7
• 2.8.8
• 2.8.9
• 2.8.10
• 2.8.11
• 2.8.12
• 2.8.13
• 2.8.14
• 2.8.15
• 2.8.16
• 2.8.17
• 2.8.18

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion