Anonymous cache poisoning via XHR requests in Discourse
Discourse is an open source platform for community discussion. An attacker can make several XHR requests until the cache is poisoned with a response without any preloaded data. This issue only affects anonymous visitors of the site. This problem has been patched in the latest version of Discourse. Users are advised to upgrade. Users unable to upgrade should disable anonymous cache by setting the `DISCOURSE_DISABLE_ANON_CACHE` environment variable to a non-empty value.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for help- Published
- Oct 8, 2024
- Updated
- Jun 17, 2026
- EPSS
- 1.7% · 76th percentile
- CWE
- CWE-610
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Report tools
Action score
32
Monitor
Low priority for now.
- CVSS
- 32 / 40 · 8.2 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.7%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 8.2
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| discourse | discourse | cpe:2.3:a:discourse:discourse |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- discourse discoursebefore 3.3.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
discourse discourse
- stable: < 3.3.2, tests-passed: < 3.4.0.beta2affected
Same product
discourse: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-41163RCE via malicious SNS subscription payload45Plan
- CVE-2025-68662FinalDestination hostname matching allows SSRF protection bypass39Monitor
- CVE-2023-47121Discourse SSRF vulnerability in Embedding39Monitor
- CVE-2026-55674Discourse: Cache poisoning/XSS via color scheme cookies37Monitor
- CVE-2026-53963Discourse: Stored-XSS in 2FA delete confirmation modal36Monitor
- CVE-2024-49765Bypass of Discourse Connect using other login paths if enabled in Discourse36Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Exploit-DB entry ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | webapps | 2025-07-08 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- First PoC+272 d
- TodaySep 30, 2026+722 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- high · data or configuration can be modified
- Availability
- low · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- Low
Weakness class (CWE)
CWE-610 · Externally Controlled Reference to a Resource in Another SphereCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.