PaperCut NG/MF Cross-Site Request Forgery (CSRF)
CVE-2023-2533 is a high-severity cross-site request forgery vulnerability in PaperCut NG/MF from PaperCut, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 2.1.1 as the first without the flaw, so updating PaperCut NG/MF to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on July 28, 2025, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update PaperCut NG/MF to 2.1.1 or a later version.
- Update Papercut Mf to 20.1.8 or 21.2.12 or 22.1.1, whichever matches your release line, or a later version.
- Update Papercut Ng to 20.1.8 or 21.2.12, whichever matches your release line, or a later version.
- CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- 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.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| PaperCut | PaperCut NG/MF | 22.0.10 up to, but not including, 2.1.1 | 2.1.1 |
| Papercut | Papercut Mf | before 20.1.8; 21.0.0 up to, but not including, 21.2.12; 22.0.0 up to, but not including, 22.1.1 | 20.1.8, 21.2.12, 22.1.1 |
| Papercut | Papercut Ng | before 20.1.8; 21.0.0 up to, but not including, 21.2.12; 22.0.0 through 22.1.1 | 20.1.8, 21.2.12 |
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
- RequiredA user must take an action such as opening a file or link.
- 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:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.4 | High | CNA (fluidattacks.com) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
A Cross-Site Request Forgery (CSRF) vulnerability has been identified in PaperCut NG/MF, which, under specific conditions, could potentially enable an attacker to alter security settings or execute arbitrary code. This could be exploited if the target is an admin with a current login session. Exploiting this would typically involve the possibility of deceiving an admin into clicking a specially crafted malicious link, potentially leading to unauthorized changes.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Cross-Site Request Forgery
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.
How developers prevent this class of flaw
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, use anti-CSRF packages such as the OWASP CSRFGuard. Another example is the ESAPI Session Management control, which includes a component for CSRF.
- Ensure that the application is free of cross-site scripting issues (CWE-79), because most CSRF defenses can be bypassed using attacker-controlled script.
- Generate a unique nonce for each form, place the nonce into the form, and verify the nonce upon receipt of the form. Be sure that the nonce is not predictable (CWE-330).
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-2533US Government Resource
Technical write-ups (may include proof of concept)
- fluidattacks.com/advisories/arcangel/Exploit, Third Party Advisory
Other vulnerabilities in PaperCut NG/MF
- 7.3 High severity
- 7.5 High severity
- 8.1 High severity
- 7.5 High severity
Recent Cross-Site Request Forgery vulnerabilities
- 8.8 High severity
- 8.0 High severity
- 8.8 High severity
- 8.1 High severity
- 8.0 High severity
- 8.8 High severity
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