CVE-2026-72727
CVE-2026-72727 — Discourse: Stored XSS in the moderation review queue
Discourse is an open-source discussion platform. Prior to 026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, a low-privileged user could place crafted content in the moderation review queue that executed stored cross-site scripting when a moderator viewed it on a site with a modified or disabled default Content Security Policy. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
Published Updated Sources: NVD, discourse (CNA), GitHub, SOCRadar CTI
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Exploit code
public exploit, none observed
EPSS
0%
ahead of 0% of scored CVEs
CVSS base
4.8
medium
Remediation
The vendor's own words where we have them.
Upgrade discourse to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.
First 24 hours
Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.
- Identify exposed assets running affected vendor/product/version combinations.
- Prioritize based on EPSS, PoC availability, and external exposure.
- Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.
Affected scope
Vendor, product and version as the advisories word them.
| Vendor | Product | Versions | Status |
|---|---|---|---|
| discourse | discourse | < 2026.1.6 | Vulnerable |
| discourse | discourse | >= 2026.5.0-latest, < 2026.5.2 | Vulnerable |
| discourse | discourse | >= 2026.6.0-latest, < 2026.6.1 | Vulnerable |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Scope
X
Attack Complexity
Low
Attack Vector
Network
Privileges Req
Low
User Interaction
A
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 4.8 | CVSS 4.0 | medium | — | — | discourse (CNA) |
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
What this weakness leads to
MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Bypass Protection Mechanism
- Read Application Data
- Execute Unauthorized Code or Commands
Mitigation: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples of libraries and frameworks that make it easier to generate properly encoded output include Microsoft's Anti-XSS library, the OWASP ESAPI Encoding module, and Apache Wicket.
Weakness & attack patterns
- CWE-79Cross-site Scripting
Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.
Public exploit
Capability, not use: code existing is a different claim from anyone running it.
Repositories
1
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Prioritize edge telemetry for network-reachable discourse.
- Monitor for scanner or exploit-pattern traffic after 1 public PoC repositories were reported.
Timeline
What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.
- 2026
Added · CVSS 3.1 4.8 (AV:N)
Aug 10, 2026 · NVD
Initial · CVE published
Aug 10, 2026 · NVD
Source activity
Readings a source repeats on a schedule, counted rather than listed.
- 1×CVE modified by NIST, Modified, LinkAug 10, 2026 · SOCRadar CTI
References
1 on the record
- github.com/discourse/discourse/security/advisories/GHSA-pq6q-p5g3-rj54
Exploit, Third Party Advisory
Elsewhere on this site
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1
What should defenders know first?
CVE-2026-72727 is Discourse: Stored XSS in the moderation review queue, a medium vulnerability affecting discourse from discourse. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-72727. Public exploit evidence is: 1 public PoC repositories reported; 0 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 4.8 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.