discourse: Insecure Automated Optimizations
CVE-2025-48877 is a critical-severity insecure automated optimizations vulnerability in discourse, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected discourse versions: < 3.4.4; < 3.5.0.beta5; < 3.5.0.beta6-dev. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.43% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of discourse you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Discourse | discourse | < 3.4.4; < 3.5.0.beta5; < 3.5.0.beta6-dev | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.1 | High | CNA (github.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
Discourse is an open-source discussion platform. Prior to version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of the `beta` branch, and version 3.5.0.beta6-dev of the `tests-passed` branch, Codepen is present in the default `allowed_iframes` site setting, and it can potentially auto-run arbitrary JS in the iframe scope, which is unintended. This issue is patched in version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of the `beta` branch, and version 3.5.0.beta6-dev of the `tests-passed` branch. As a workaround, the Codepen prefix can be removed from a site's `allowed_iframes`.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Insecure Automated Optimizations
The product uses a mechanism that automatically optimizes code, e.g. to improve a characteristic such as performance, but the optimizations can have an unintended side effect that might violate an intended security assumption.
More Insecure Automated Optimizations vulnerabilities (CWE-1038)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in discourse
- 7.7 High severity
- 7.5 High severity
- 7.5 High severity
- 7.2 High severity
- 8.7 High severity
- 9.3 Critical severity
Recent Insecure Automated Optimizations vulnerabilities
- 7.8 High severity
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