CVE-2023-27351

Exp

This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914). Authentication is not required to exploit this vulnerability. The specific flaw exists within the SecurityRequestFilter class. The issue results from improper implementation of the authentication algorithm. An attacker can leverage this vulnerability to bypass authentication on the system. Was ZDI-CAN-19226.

Published: 2023-04-20 Last update: 2026-04-21 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-27351 is rated Critical Active Threat (88.6/100): CVSS High severity, with high exploitation likelihood (EPSS 83.28%, 99th percentile). CISA KEV confirms active exploitation (added 2026-04-20) affecting PaperCut / NG/MF. an authentication bypass (CWE-287) Unauthenticated remote administrative access may be possible. Assess exposure and apply mitigations immediately; prioritize emergency patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA Known Exploited Vulnerabilities Catalog for CVE-2023-27351

KEV catalog lead: This CVE appears in the CISA Known Exploited Vulnerabilities catalog (in-the-wild exploitation signal). Full KEV detail: CVE-2023-27351 on KEV · Exploit-DB search ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-27351

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-24 84.44% 83.28% -1.15%
2 2026-05-23 86.80% 84.44% -2.36%
3 2026-05-22 — 86.80% —

Full EPSS history (46 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-27351

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
8.2 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 4.2 [email protected]

Weakness enumeration for CVE-2023-27351

GitHub Security Advisory for CVE-2023-27351

GHSA-2c69-r2jh-xjvm · Severity: high — This vulnerability allows remote attackers to bypass authentication on affected installations of...

Affected software / configurations for CVE-2023-27351

Vendor Product Version Raw CPE
papercut papercut_mf >= 15.0, < 20.1.7 cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*
papercut papercut_mf >= 21.0.0, < 21.2.11 cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*
papercut papercut_mf >= 22.0.0, < 22.0.9 cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*
papercut papercut_ng >= 15.0, < 20.1.7 cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*
papercut papercut_ng >= 21.0.0, < 21.2.11 cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*
papercut papercut_ng >= 22.0.0, < 22.0.9 cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*

References for CVE-2023-27351

cvelogic Threat Intelligence