Summary
Cookies are sent to external images in rendered diff (and server side request forgery)
Workarounds
As a workaround, the image embedding feature can be disabled by deleting xwiki-platform-diff-xml-<version>.jar in WEB-INF/lib/.
References
Impact
The rendered diff in XWiki embeds images to be able to compare the contents and not display a difference for an actually unchanged image. For this, XWiki requests all embedded images on the server side. These requests are also sent for images from other domains and include all cookies that were sent in the original request to ensure that images with restricted view right can be compared. This allows an attacker to steal login and session cookies that allow impersonating the current user who views the diff. The attack can be triggered with an image that references the rendered diff, thus making it easy to trigger.
More concretely, to reproduce, add 101 different images with references to the attacker's server. In any place add an image with a reference to /xwiki/bin/view/Image%20Cookie%20Test/?xpage=changes&rev1=1.1&rev2=2.1&include=renderedChanges where Image%20Cookie%20Test needs to be replaced by the path to the document with the images and the two revisions should match the revision before/after adding the images. Whenever a user views that image, the user's login cookies should be sent to the attacker's server. The 101 images are to circumvent the cache that has a default maximum size of 100 entries.
Apart from stealing login cookies, this also allows server-side request forgery (the result of any successful request is returned in the image's source) and viewing protected content as once a resource is cached, it is returned for all users. As only successful requests are cached, the cache will be filled by the first user who is allowed to access the resource.
Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.
CVE-2023-48240 has a CVSS score of 9.0 (Critical). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (14.10.15, 15.5.1, 15.6); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
This has been patched in XWiki 14.10.15, 15.5.1 and 15.6. The rendered diff now only downloads images from trusted domains. Further, cookies are only sent when the image's domain is the same the requested domain. The cache has been changed to be specific for each user.
Frequently Asked Questions
- What is CVE-2023-48240? CVE-2023-48240 is a critical-severity server-side request forgery (SSRF) vulnerability in org.xwiki.platform:xwiki-platform-diff-xml (maven), affecting versions >= 11.10.1, < 14.10.15. It is fixed in 14.10.15, 15.5.1, 15.6. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
- How severe is CVE-2023-48240? CVE-2023-48240 has a CVSS score of 9.0 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of org.xwiki.platform:xwiki-platform-diff-xml are affected by CVE-2023-48240? org.xwiki.platform:xwiki-platform-diff-xml (maven) versions >= 11.10.1, < 14.10.15 is affected.
- Is there a fix for CVE-2023-48240? Yes. CVE-2023-48240 is fixed in 14.10.15, 15.5.1, 15.6. Upgrade to this version or later.
- Is CVE-2023-48240 exploitable, and should I be worried? Whether CVE-2023-48240 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2023-48240 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2023-48240?
- Upgrade
org.xwiki.platform:xwiki-platform-diff-xmlto 14.10.15 or later - Upgrade
org.xwiki.platform:xwiki-platform-diff-xmlto 15.5.1 or later - Upgrade
org.xwiki.platform:xwiki-platform-diff-xmlto 15.6 or later
- Upgrade