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Fencer Intel
medium 5.4

CVE-2021-31330 json

A Cross-Site Scripting (XSS) vulnerability exists within Review Board versions 3.0.20 and 4.0 RC1 and earlier.

published 4y ago modified 4mo ago also BIT-reviewboard-2021-31330 , EUVD-2021-18240

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 57%
public exploits
0
none known

Summary

A Cross-Site Scripting (XSS) vulnerability exists within Review Board versions 3.0.20 and 4.0 RC1 and earlier. An authenticated attacker may inject malicious Javascript code when using Markdown editing within the application which remains persistent.

Is CVE-2021-31330 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

0.82% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • mattschmidt.net https://mattschmidt.net/2021/04/14/review-board-xss-discovered/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N
OSV 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
bitnami reviewboard
>=3.0.20, <=3.0.20
>=4.0-beta1.0, <=4.0-beta1.0
>=4.0-beta2.0, <=4.0-beta2.0
>=4.0-rc1.0, <=4.0-rc1.0
 no fix listed

Classification

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

References

Sources

Fencer Intel 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.