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Fencer Intel
high 7.5

CVE-2026-55420 json

Discourse: Remote code execution via pdf uploads

published 4mo ago modified 2mo ago also BIT-discourse-2026-55420 , EUVD-2026-42665 , GHSA-7wq5-jgww-5rw3

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, under certain non-default configurations, processing of PDF uploads could be exploited to obtain RCE on the server. This issue is patched in 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

Patch / fix

  • bitnami discourse 2026.1.5, 2026.4.2, 2026.5.1, 2026.7.0
  • discourse discourse 2026.1.5, 2026.4.2, 2026.5.1

Is CVE-2026-55420 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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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
3mo ago

Exploit prediction

0.60% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
OSV 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
bitnami discourse
>=2026.1.0, <2026.1.5
>=2026.4.0, <2026.4.2
>=2026.5.0, <2026.5.1
>=2026.6.0, <2026.7.0
2026.1.5
2026.4.2
2026.5.1
2026.7.0

Affected products

  • discourse discourse

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

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.