CVE-2025-8550VulnerabilityPublished 5 Aug 2025

CVE-2025-8550: atjiu pybbs · Cross Site Scripting

Affects atjiu pybbsSource CVE Database V5

Not known to be exploited · public exploit available (Exploit-DB) · CVSS 4.8 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score

4.8Medium

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

EPSS: 0.6% chance of exploitation in 30 days – higher than 50% 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

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 5 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
1 Exploit-DB entry, 6 days after disclosure
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

CVE ID reserved
by VulDB
2025-08-0413:04Z, 18 hours before disclosure
CVE published
on cve.org
2025-08-0507:02Z, t = 0
In Threat Radar
record ingested
2025-08-0507:17Z, 16 minutes after disclosure
First Exploit-DB entry (opens in a new tab)
atjiu pybbs 6.0.0 - Cross Site Scripting (XSS)
2025-08-11, 6 days after disclosure

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 2026-10-26.

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

Organizations should immediately apply the patch identified by commit 2fe4a51afbce0068c291bc1818bbc8f7f3b01a22 to remediate the vulnerability. Beyond patching, it is critical to implement strict input validation and output encoding on all user-supplied data, especially in administrative interfaces. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. Limit administrative access to trusted networks and use multi-factor authentication (MFA) to reduce the risk of compromised credentials. Conduct regular security awareness training to reduce the risk of phishing attacks that could trigger user interaction exploitation. Monitor logs for unusual activity on the /admin/topic/list endpoint and implement web application firewalls (WAF) with rules targeting XSS patterns. Finally, consider isolating the pybbs administrative interface behind VPN or zero-trust network access solutions to further reduce exposure.

Description

A vulnerability was found in atjiu pybbs up to 6.0.0. It has been declared as problematic. Affected by this vulnerability is an unknown functionality of the file /admin/topic/list. The manipulation of the argument Username leads to cross site scripting. The attack can be launched 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 version 6.0.0 or earlier, this vulnerability poses a risk primarily to administrative users who access the /admin/topic/list page. Successful exploitation could lead to session hijacking or unauthorized actions performed under the context of an admin user, potentially compromising forum integrity and exposing sensitive user data. This could damage organizational reputation, especially for entities relying on pybbs for community engagement or internal communications. Given the requirement for high privileges and user interaction, the threat is somewhat mitigated but remains significant in environments where administrative users might be targeted via phishing or social engineering. The impact is more pronounced in sectors with strict data protection regulations such as GDPR, where unauthorized data exposure could lead to regulatory penalties. Additionally, if pybbs is integrated with other internal systems, the compromise could serve as a pivot point for broader network intrusion.

Summary

CVE-2025-8550 is a cross-site scripting (XSS) vulnerability identified in the atjiu pybbs software, specifically affecting versions up to 6.0.0. The vulnerability resides in the /admin/topic/list functionality, where improper sanitization or validation of the 'Username' argument allows an attacker to inject malicious scripts. This flaw enables remote attackers to execute arbitrary JavaScript code in the context of the victim's browser without requiring authentication, although the CVSS vector indicates a requirement for high privileges (PR:H) and user interaction (UI:P). The vulnerability has been publicly disclosed, and a patch identified by commit hash 2fe4a51afbce0068c291bc1818bbc8f7f3b01a22 is available to remediate the issue. The CVSS 4.0 base score is 4.8, categorizing it as a medium severity vulnerability. The attack vector is network-based (AV:N), with low attack complexity (AC:L), but requires user interaction and high privileges, limiting the ease of exploitation. The impact primarily affects the integrity and confidentiality of user sessions by potentially allowing session hijacking, credential theft, or unauthorized actions within the affected administrative interface. The vulnerability does not affect availability or system-level integrity directly. No known exploits are currently active in the wild, but public disclosure increases the risk of exploitation attempts.

References

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Exploitation evidence

Timeline

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Aug 2025, 07:32 UTC

Public exploits and detection1 Exploit-DB entry

Technical details

References

Community reviews

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