CVE-2026-33426Network attack vector

Restricted-tag modification via missing visibility authorization

Published Mar 20, 2026 · Updated Mar 20, 2026

Missing authorization in Discourse before 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 allows remote authenticated users to alter hidden tags. The tag-editing and synonym-creation paths accept tags hidden by restricted tag groups without enforcing the caller's visibility; Discourse has not identified the affected function. Exploitation requires tag-editing permission and permits unauthorized changes to tag metadata that remains hidden from the user.

CVSS severity3.5
Low
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Discourse before 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 allows remote authenticated users to alter hidden tags. The tag-editing and synonym-creation paths accept tags hidden by restricted tag groups without enforcing the caller's visibility; Discourse has not identified the affected function. Exploitation requires tag-editing permission and permits unauthorized changes to tag metadata that remains hidden from the user.

The record

CVE
CVE-2026-33426
Published
Mar 20, 2026
Updated
Mar 20, 2026
Vendor
Discourse
Product
Discourse
Classifications
CWE-862, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 20, 2026Record 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=>= 2026.1.0-latest, < 2026.1.2
  2. Affected versionversion=>= 2026.2.0-latest, < 2026.2.1
  3. Affected versionversion== 2026.3.0-latest

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Discourse · Discourseversion=>= 2026.1.0-latest, < 2026.1.2; version=>= 2026.2.0-latest, < 2026.2.1; version== 2026.3.0-latest

Published CVSS scores

3.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N
3.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

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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