PaperCut NG: Unrestricted Upload of File with Dangerous Type
CVE-2023-3486 is a high-severity unrestricted upload of file with dangerous type vulnerability in PaperCut NG from PaperCut, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 22.1.3 as the first without the flaw, so updating PaperCut NG to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 79.2% chance of exploitation within 30 days, which is in the top 0.4% of all scored CVEs.
Exploitation in the next 30 days is more likely than not, according to EPSS.
What to do
- Update PaperCut NG to 22.1.3 or a later version.
- Update Papercut Mf to 22.1.3 or a later version.
- Read the advisory on papercut.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 |
|---|---|---|---|
| PaperCut | PaperCut NG | before 22.1.3 | 22.1.3 |
| Papercut | Papercut Mf | before 22.1.3 | 22.1.3 |
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
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.2 | High | CNA (tenable.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
An authentication bypass exists in PaperCut NG versions 22.0.12 and prior that could allow a remote, unauthenticated attacker to upload arbitrary files to the PaperCut NG host’s file storage. This could exhaust system resources and prevent the service from operating as expected.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Unrestricted Upload of File with Dangerous Type
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
How developers prevent this class of flaw
- Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.
- When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
- Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically.
More Unrestricted Upload of File with Dangerous Type vulnerabilities (CWE-434)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- tenable.com/security/research/tra-2023-23Third Party Advisory
Other vulnerabilities in PaperCut NG
- 9.1 Critical severity
PaperCut NG/MF Unsafe Reflection Exploited
- 9.8 Critical severity
- 8.1 High severity
- 7.2 High severity
- 7.8 High severity
- 7.8 High severity
Recent Unrestricted Upload of File with Dangerous Type vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 8.8 High severity
- 7.2 High severity
- 9.8 Critical severity
- 9.8 Critical severity
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