Sisimai up to 4.25.14p11 lib/sisimai/string.rb to_plain redos

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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A vulnerability has been found in Sisimai up to 4.25.14p11 and classified as problematic. This vulnerability affects the function to_plain of the file lib/sisimai/string.rb. The manipulation with an unknown input leads to a redos vulnerability. The CWE definition for the vulnerability is CWE-1333. The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles. As an impact it is known to affect availability.

The weakness was disclosed 01/16/2023 as 244. The advisory is shared for download at This vulnerability was named CVE-2022-4891. Technical details and also a public exploit are known. The MITRE ATT&CK project declares the attack technique as T1449.003.

It is possible to download the exploit at It is declared as proof-of-concept.

Upgrading to version 4.25.14p12 eliminates this vulnerability. The upgrade is hosted for download at Applying the patch 51fe2e6521c9c02b421b383943dc9e4bbbe65d4e is able to eliminate this problem. The bugfix is ready for download at The best possible mitigation is suggested to be upgrading to the latest version. The advisory contains the following remark:

Prevent Regex Denial of Service in Sisimai::String.to_plain




  • open-source

CPE 2.3info

CPE 2.2info


VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.7

VulDB Base Score: 3.5
VulDB Temp Score: 3.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔒

CNA Base Score: 3.5
CNA Vector (VulDB): 🔒



VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

NVD Base Score: 🔒


Class: Redos
CWE: CWE-1333 / CWE-400 / CWE-404
ATT&CK: T1449.003

Local: No
Remote: Partially

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒


Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍


Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Sisimai 4.25.14p12
Patch: 51fe2e6521c9c02b421b383943dc9e4bbbe65d4e


01/16/2023 Advisory disclosed
01/16/2023 +0 days CVE reserved
01/16/2023 +0 days VulDB entry created
02/09/2023 +24 days VulDB last update


Advisory: 244
Status: Confirmed

CVE: CVE-2022-4891 (🔒)
scip Labs:


Created: 01/16/2023 07:49 PM
Updated: 02/09/2023 08:36 AM
Changes: 01/16/2023 07:49 PM (47), 02/09/2023 08:34 AM (2), 02/09/2023 08:36 AM (28)
Complete: 🔍


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