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Fencer Vulns
low 3.5

CVE-2026-4494 json

atjiu pybbs TopicApiController.java create cross site scripting

published 2026-03-20 7 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-13756

cvss
3.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

A vulnerability was identified in atjiu pybbs 6.0.0. This affects the function create of the file src/main/java/co/yiiu/pybbs/controller/api/TopicApiController.java. The manipulation leads to cross site scripting. It is possible to initiate the attack remotely. The exploit is publicly available and might be used.

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • fx4tqqfvdw4.feishu.cn https://fx4tqqfvdw4.feishu.cn/docx/EKVgdqWIzo70C0xB5jxcb4IZnre?from=from_copylink referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 5.1 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
CNA 3.1 3.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA 3.0 3.5 CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:P/A:N/E:POC/RL:ND/RC:UR
CNA 4.0 2.0 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA 3.1 3.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
CNA 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:P/A:N

Affected products

  • atjiu pybbs

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.