CVE-2026-27454

mediumpriority · track · 0OT risk · elevatedEPSS 0.010 · 61 %ileEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.96% (61st) EPSS
CVSS 5.3 · medium
Is it mine?
9 products
Check your exposure
Who says so?
4 sources
cnnvd · enisa_euvd · osv · nvd

EPSS · scored 2026-10-27

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, requesting /posts/:id.json?version=X bypassed authorization checks on post revisions. The display_post method called post.revert_to directly without verifying whether the revision was hidden or if the user had permission to view edit history. This meant hidden revisions (intentionally concealed by staff) could be read by any user by simply enumerating version numbers. Starting in versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, Discourse looks up the PostRevision and call guardian.ensure_can_see! before reverting, consistent with how the /posts/:id/revisions/:revision endpoint already authorizes access. No known workarounds are available.

01

cvss

Technical severity, 0–10. One row per scoring source.

5.3
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:Nsecondary · ENISA EU
v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:Nsecondary · security-advisories@github.comexploitability 3.9 · impact 1.4
v3.15.2mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:Fsecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-862US
04

affected products (9)

Products and version ranges known to be affected.

05

advisories (1)

Vendor and ecosystem advisories describing this.

  • BIT-discourse-2026-27454Discourse has check revision visibility on posts endpoint2026-03-27vendor · osvUS

    Discourse is an open-source discussion platform. Prior to versions 2026.3.0, 2026.2.1, and 2026.1.2, requesting /posts/:id.json?version=X bypassed authorization checks on post revisions. The display_post method called post.revert_to directly without verifying whether the revision was hidden or if the user had permission to view edit history. This meant hidden revisions (intentionally concealed by staff) could be read by any user by simply enumerating version numbers. Starting in versions 2026.3.0, 2026.2.1, and 2026.1.2, Discourse looks up the PostRevision and call guardian.ensure_can_see! before reverting, consistent with how the /posts/:id/revisions/:revision endpoint already authorizes access. No known workarounds are available.

06

also known as (3)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdosvnvdNVDCVE.orgMITRE
published 2026-03-19modified 2026-06-17
08

references (13)

External citations — patches, advisories, analysis.

scry

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