VulnerabilityPublished 5 Aug 2025

CVE-2025-8547: atjiu pybbs · Improper Authorization

Affects atjiu pybbsSource CVE Database V5

Public exploit available · CVSS 6.9 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 4.0 base score

6.9Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 37% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/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: None
User Interaction: None
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: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
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: 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
atjiu pybbs	Affected =6.0	Fixed in–

AI-suggested

European organizations should immediately verify if they are running atjiu pybbs version 6.0.0 or earlier and prioritize patching with the update identified by the patch hash 044f22893bee254dc2bb0d30f614913fab3c22c2. Beyond patching, organizations should audit their email verification workflows to ensure robust authorization checks are in place. Implement network-level access controls to restrict exposure of pybbs services to trusted IP ranges or VPNs where feasible. Employ web application firewalls (WAFs) with custom rules to detect and block suspicious requests targeting the Email Verification Handler endpoints. Regularly monitor logs for unusual activity related to email verification processes, such as repeated unauthorized attempts or anomalies in user verification status changes. Additionally, enforce multi-factor authentication (MFA) for user accounts to mitigate the impact of potential account compromise. Finally, conduct security awareness training to alert users about phishing risks that could exploit compromised verification mechanisms.

Description

A vulnerability has been found in atjiu pybbs up to 6.0.0 and classified as critical. This vulnerability affects unknown code of the component Email Verification Handler. The manipulation leads to improper authorization. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 044f22893bee254dc2bb0d30f614913fab3c22c2. 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 moderate risk. The improper authorization in the email verification process could allow attackers to bypass security controls, potentially leading to unauthorized account access or manipulation of user verification status. This can undermine trust in user identity management and may facilitate further attacks such as phishing or social engineering. Organizations relying on pybbs for community forums, customer support, or internal communications could see disruption or compromise of user accounts. Given the remote exploitability without authentication, attackers can target exposed pybbs installations over the internet, increasing the attack surface. The impact is particularly relevant for sectors with strict data protection regulations, such as finance, healthcare, and government, where unauthorized access could lead to compliance violations under GDPR and other frameworks. However, since the vulnerability does not affect confidentiality or availability directly, the immediate risk to sensitive data leakage or service disruption is limited but should not be underestimated.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Aug 2025, 06:02 UTC

Technical details

References

Community reviews

Related threats