CVE-2023-27351Known exploitationNetwork attack vector

User data disclosure via SecurityRequestFilter bypass

Published Apr 20, 2023 · Updated Apr 21, 2026

Authentication bypass in PaperCut NG/MF allows remote attackers to read stored user account data from Application Servers. SecurityRequestFilter improperly implements request authentication, permitting protected user-information retrieval without a login. The flaw affects Application Servers on all operating systems; exposed data includes usernames, contact details, card numbers, and hashes for PaperCut-created users.

CVSS severity7.5
High
EPSS probability78.05%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in PaperCut NG/MF allows remote attackers to read stored user account data from Application Servers. SecurityRequestFilter improperly implements request authentication, permitting protected user-information retrieval without a login. The flaw affects Application Servers on all operating systems; exposed data includes usernames, contact details, card numbers, and hashes for PaperCut-created users.

The record

CVE
CVE-2023-27351
Published
Apr 20, 2023
Updated
Apr 21, 2026
Vendor
PaperCut
Product
PaperCut NG/MF
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 20, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=22.0.5 (Build 63914)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PaperCut · PaperCut NG/MFversion=22.0.5 (Build 63914)

Published CVSS scores

8.2Zero Day InitiativeCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsShadowserver observations through Sep 16, 2026. Gaps indicate unavailable data.
Sep 10, 2026Sep 16, 2026
View daily counts
Reporting dayUnique IPs
Sep 10, 20265
Sep 11, 20261
Sep 12, 2026Unavailable
Sep 13, 2026Unavailable
Sep 14, 20261
Sep 15, 2026Unavailable
Sep 16, 20262
Latest reporting daySep 16, 2026
Latest daily unique IPs2
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

See the directory against your own environment.

Your stack

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