VulnerabilityPublished 16 Feb 2026Updated 23 Feb 2026

CVE-2026-2557: cskefu · Cross-site Scripting

Affects cskefuSource CVE Database V5

Public exploit available · CVSS 5.1 Medium.

Data as of 26 Oct 2026, 10:12 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 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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:P

Base metrics

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

Threat metrics

Exploit Maturity: POC

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.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 16 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CVSS exploit maturity: proof of concept public
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), CVSS vector, 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

Affected software

Product	Affected	Fixed in
cskefu	Affected =8.0.0 =8.0.1	Fixed in–

CPE configurations (1)

cpe:2.3:a:cskefu:cskefu:*:*:*:*:*:*:*:*

AI-suggested

Immediate mitigation should include disabling or restricting the file upload functionality in cskefu until a patch is available.
Implement strict input validation and sanitization on all file upload parameters to prevent script injection.
Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers.
Educate users about the risks of clicking unknown links or opening suspicious files related to the platform.
Monitor web application logs for unusual file upload activity or attempts to inject scripts.
If possible, deploy web application firewalls (WAF) with rules targeting common XSS payloads specific to cskefu upload endpoints.
Regularly check for vendor updates or community patches addressing this vulnerability.
Consider isolating the cskefu application in a segmented network zone to limit potential lateral movement.
Conduct security assessments and penetration tests focusing on file upload and input handling mechanisms. These steps go beyond generic advice by focusing on immediate operational controls and layered defenses tailored to the vulnerable component.

Description

A vulnerability was detected in cskefu up to 8.0.1. Impacted is the function Upload of the file com/cskefu/cc/controller/resource/MediaController.java of the component File Upload. The manipulation results in cross site scripting. The attack may be launched remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Impact

The primary impact of CVE-2026-2557 is the potential compromise of user confidentiality and integrity through the execution of arbitrary scripts in the victim's browser. This can lead to session hijacking, theft of sensitive information such as cookies or credentials, and unauthorized actions performed on behalf of the user. While the vulnerability does not directly affect system availability or server integrity, successful exploitation can erode user trust and lead to reputational damage. Organizations relying on cskefu for customer service or communication may face increased risk of targeted phishing or social engineering attacks leveraging this vulnerability. The lack of vendor response and patch availability increases the window of exposure, potentially inviting attackers to develop and deploy exploits. The medium severity score reflects the balance between ease of exploitation and limited scope of impact, but the risk is amplified in environments with high user interaction and sensitive data exchange.

References

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