CVE-2025-8550Public exploitNetwork attack vector

Administrator-browser script execution via unencoded username

Published Aug 5, 2025 · Updated Aug 5, 2025

Reflected XSS in atjiu pybbs 6.0.0 and earlier allows remote authenticated users to execute script in an administrator's browser. The /admin/topic/list page returns the username query parameter without HTML encoding; the patch instead sanitizes request values with Jsoup. An administrator must open the crafted authenticated page, after which the script runs in the pybbs origin and can act through that session.

CVSS severity5.4
Medium
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in atjiu pybbs 6.0.0 and earlier allows remote authenticated users to execute script in an administrator's browser. The /admin/topic/list page returns the username query parameter without HTML encoding; the patch instead sanitizes request values with Jsoup. An administrator must open the crafted authenticated page, after which the script runs in the pybbs origin and can act through that session.

The record

CVE
CVE-2025-8550
Published
Aug 5, 2025
Updated
Aug 5, 2025
Vendor
atjiu
Product
pybbs
Classifications
CWE-94, CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

atjiu · pybbsversion=6.0

Published CVSS scores

3.3VulDBAV:N/AC:L/Au:M/C:N/I:P/A:N
1.9VulDBCVSS: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
5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
2.4VulDBCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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