CVE-2025-11276VulnerabilityPublished 5 Oct 2025Updated 6 Oct 2025

CVE-2025-11276: Rebuild · Cross Site Scripting

Affects RebuildSource CVE Database V5

Not known to be exploited · CVSS 5.1 Medium · fixed in 4.1.4 : update Rebuild when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

5.1Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.1.4

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: Passive
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: Passive: Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 5 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Rebuild	Affected =4.1.0 =4.1.1 =4.1.2 =4.1.3	Fixed in–

AI-suggested

Organizations should immediately upgrade Rebuild installations to version 4.1.4 or later to remediate the vulnerability. In addition to patching, implement robust input validation and output encoding on all user-supplied data, especially in comment and guestbook modules, to prevent injection of malicious scripts. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. Regularly audit web application logs for suspicious comment submissions or unusual user activity indicative of attempted XSS exploitation. Educate users about the risks of clicking unknown links or interacting with untrusted content. Consider deploying web application firewalls (WAFs) with rules tuned to detect and block XSS payloads targeting the affected component. Finally, maintain an up-to-date inventory of Rebuild deployments across the organization to ensure no vulnerable instances remain unpatched.

Description

A security flaw has been discovered in Rebuild up to 4.1.3. Affected by this issue is some unknown functionality of the component Comment/Guestbook. Performing manipulation results in cross site scripting. It is possible to initiate the attack remotely. Upgrading to version 4.1.4 can resolve this issue. It is suggested to upgrade the affected component. According to the researcher the vendor has confirmed the flaw and fix in a private issue response.

Impact

For European organizations, this vulnerability poses a moderate risk primarily to web applications leveraging the Rebuild platform with the vulnerable Comment/Guestbook component. Successful exploitation could lead to session hijacking, unauthorized actions performed on behalf of users, or defacement of web content, potentially damaging organizational reputation and user trust. Confidential data accessible through user sessions could be compromised, and integrity of displayed content could be undermined. While availability impact is negligible, the breach of confidentiality and integrity could violate GDPR requirements, leading to regulatory scrutiny and fines. Organizations with high volumes of user interaction on public-facing sites are at greater risk. The lack of known exploits reduces immediate threat, but the ease of exploitation and remote attack vector necessitate prompt remediation to prevent opportunistic attacks. The medium severity suggests prioritization but not emergency response, balancing resource allocation with risk.

Summary

CVE-2025-11276 identifies a cross-site scripting vulnerability in the Comment/Guestbook component of the Rebuild software, affecting versions 4.1.0 through 4.1.3. This vulnerability arises from improper input validation or output encoding in the affected component, allowing an attacker to inject malicious JavaScript code remotely. The attack vector is network-based with no authentication required, but user interaction is necessary to execute the malicious script, typically by tricking a user into clicking a crafted link or viewing a manipulated comment. The vulnerability impacts the confidentiality and integrity of user sessions by enabling potential session hijacking, credential theft, or content manipulation. The CVSS 4.0 base score of 5.1 reflects a medium severity, considering the ease of exploitation (low complexity), no privileges required, but requiring user interaction and limited impact on availability. The vendor has confirmed the flaw and released a fix in version 4.1.4, which addresses the input validation issues. No public exploits have been reported, indicating limited active exploitation. The vulnerability is relevant for organizations using Rebuild for web applications that allow user-generated content, especially where comments or guestbook features are enabled.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 12 Oct 2025, 13:49 UTC

Technical details

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