CVE-2025-8554VulnerabilityPublished 5 Aug 2025

CVE-2025-8554: atjiu pybbs · Cross Site Scripting

Affects atjiu pybbsSource CVE Database V5

Not known to be exploited · CVSS 4.8 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

4.8Medium

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:H/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: High
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: High: The attacker requires privileges that provide significant (e.g., administrative) control over the vulnerable system allowing full access to the vulnerable system’s settings and files.
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 5 Aug 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
atjiu pybbs	Affected =6.0	Fixed in–

AI-suggested

European organizations should prioritize applying the official patch identified by commit 2fe4a51afbce0068c291bc1818bbc8f7f3b01a22 to update pybbs to a secure version beyond 6.0.0. In addition to patching, organizations should implement strict input validation and output encoding on all user-supplied data, especially in administrative interfaces. Deploying Content Security Policy (CSP) headers can help mitigate the impact of potential XSS attacks by restricting script execution contexts. Administrators should be trained to recognize phishing attempts and suspicious URLs to reduce the risk of user interaction leading to exploitation. Regular security audits and penetration testing focused on web application vulnerabilities can help identify similar issues proactively. Finally, monitoring web server logs and application behavior for anomalous requests targeting /admin/user/list can provide early detection of attempted exploitation.

Description

A vulnerability, which was classified as problematic, has been found in atjiu pybbs up to 6.0.0. This issue affects some unknown processing of the file /admin/user/list. The manipulation of the argument Username leads to cross site scripting. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used. The patch is named 2fe4a51afbce0068c291bc1818bbc8f7f3b01a22. It is recommended to apply a patch to fix this issue.

Impact

For European organizations using atjiu pybbs 6.0.0 or earlier, this vulnerability poses a risk primarily to the confidentiality and integrity of administrative sessions and data. Successful exploitation could allow attackers to execute arbitrary scripts in the context of an administrator's browser, leading to session hijacking, unauthorized actions, or theft of sensitive information. Given that pybbs is a bulletin board system, organizations relying on it for internal or external communication could face reputational damage and operational disruption. The impact is heightened in sectors where sensitive discussions or data are exchanged, such as government, education, or healthcare institutions. The medium severity rating suggests that while the vulnerability is not critical, it still represents a significant risk if left unpatched, especially in environments with high administrative privileges and sensitive data. The requirement for user interaction limits automated exploitation but does not eliminate risk, as social engineering or phishing could facilitate attacks.

Summary

CVE-2025-8554 is a cross-site scripting (XSS) vulnerability identified in the atjiu pybbs product, specifically affecting versions up to 6.0.0. The vulnerability arises from improper handling of the 'Username' argument in the /admin/user/list endpoint. This improper input validation allows an attacker to inject malicious scripts that can be executed in the context of the victim's browser. The vulnerability is remotely exploitable without requiring authentication, but it does require user interaction (such as an administrator visiting a crafted URL or page). The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:H indicates high privileges required, but the description suggests no authentication is needed, so this may be a discrepancy), user interaction required (UI:P), and low impact on integrity and availability, with no impact on confidentiality. The vulnerability has been publicly disclosed, and a patch identified by commit hash 2fe4a51afbce0068c291bc1818bbc8f7f3b01a22 is available. Although no known exploits are currently in the wild, the public disclosure increases the risk of exploitation. The vulnerability is classified as medium severity due to the moderate impact and exploitation requirements. XSS vulnerabilities can lead to session hijacking, defacement, or redirection to malicious sites, potentially compromising administrative accounts and sensitive data within the affected application.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Aug 2025, 09:32 UTC

Technical details

References

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