VulnerabilityPublished 24 Dec 2024Updated 30 Aug 2025

CVE-2024-9427: Improper Encoding or Escaping of Output

Source CVE Database V5

Not known to be exploited · CVSS 5.4 Medium.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

5.4Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
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 on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Dec 2024
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 26 Oct 2026.

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 or the CVSS exploit maturity 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

AI-suggested

To mitigate CVE-2024-9427, organizations should prioritize applying any forthcoming official patches from Koji maintainers or Red Hat. In the absence of patches, implement strict input validation on all user-supplied data to ensure it does not contain executable code or special characters that could be interpreted as JavaScript. Employ comprehensive output encoding or escaping techniques on all dynamic content rendered in the web interface, particularly for reflected inputs. Utilize Content Security Policy (CSP) headers to restrict the execution of inline scripts and reduce the impact of potential XSS payloads. Regularly audit and test the Koji web interface for XSS vulnerabilities using automated scanners and manual penetration testing. Educate users about the risks of clicking on suspicious links and encourage the use of browser security features such as script blockers or anti-XSS extensions. Monitor web server logs for unusual request patterns that may indicate attempted exploitation. Finally, consider isolating Koji instances behind VPNs or internal networks to reduce exposure to external attackers.

Description

A vulnerability in Koji was found. An unsanitized input allows for an XSS attack. Javascript code from a malicious link could be reflected in the resulting web page. It is not expected to be able to submit an action or make a change in Koji due to existing XSS protections in the code

Impact

The primary impact of CVE-2024-9427 is on the confidentiality and integrity of users interacting with the Koji web interface. An attacker exploiting this vulnerability can execute arbitrary JavaScript in the victim's browser, potentially stealing session cookies, performing actions on behalf of the user, or manipulating client-side data. However, due to existing XSS protections, the attacker cannot submit actions or make changes within Koji, limiting the impact. The vulnerability does not affect system availability. Organizations relying on Koji for build and release management could face targeted attacks aimed at session hijacking or information disclosure. While no widespread exploitation is reported, the vulnerability could be leveraged in spear-phishing or targeted attacks against developers or administrators using Koji. The medium severity score reflects moderate risk, but the ease of exploitation and network accessibility mean that unpatched systems remain vulnerable to client-side compromise.

Summary

CVE-2024-9427 is a vulnerability identified in the Koji build system, where improper encoding or escaping of output leads to a reflected cross-site scripting (XSS) flaw. This vulnerability arises because user-supplied input is not properly sanitized before being reflected in the web interface, allowing an attacker to inject arbitrary JavaScript code. The injected script executes in the context of the victim's browser when they visit a crafted malicious link. Despite the ability to inject code, the existing XSS protections within Koji prevent the attacker from performing privileged actions such as submitting forms or altering data, limiting the scope of exploitation. The vulnerability has a CVSS 3.1 base score of 5.4, indicating medium severity, with an attack vector of network (remote), low attack complexity, requiring privileges (PR:L), no user interaction, and unchanged scope. The impact primarily affects confidentiality and integrity by potentially stealing session tokens or manipulating client-side data, but does not affect availability. No known exploits have been reported in the wild, and no patches or mitigation links are currently provided. The vulnerability was reserved in early October 2024 and published in late December 2024, assigned by Red Hat. This vulnerability highlights the importance of proper output encoding and input validation in web applications to prevent reflected XSS attacks.

References

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