Vulnerability Report

CVE-2026-42245

Title: DoS via crafted IMAP responses

DoS

Proof Of Concept

No public PoC currently indexed for CVE-2026-42245.

CWE Category CWE-407
Published Date May 09, 2026
Modified Date May 18, 2026
Exploit Status Not Found
Score 2.3 CVSS v4.0
Exploit Probability (EPSS)
0.09%

Vulnerability Summary

CVE-2026-42245: Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, Net::IMAP::ResponseReader has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are crafted to exhaust the client's CPU for a denial of service attack. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

Impacted Vendors

N
net-dns 1
R
ruby-lang 1

Reference Links

https://github.com/ruby/net-imap/commit/6091f7d6b1f3514cafbfe39c76f2b5d73de3ca96 https://github.com/ruby/net-imap/commit/88d95231fc8afef11c1f074453f7d75b68c9dfda https://github.com/ruby/net-imap/commit/de685f91a4a4cc75eb80da898c2bf8af08d34819 https://github.com/ruby/net-imap/releases/tag/v0.4.24 https://github.com/ruby/net-imap/releases/tag/v0.5.14 https://github.com/ruby/net-imap/releases/tag/v0.6.4 https://github.com/ruby/net-imap/security/advisories/GHSA-q2mw-fvj9-vvcw
CVSS v4.0
Source Entity [email protected]
Severity LOW
2.3
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
PASSIVE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
N/A
RAW VECTOR CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-42245 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction PASSIVE
CVSS Vector String CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected Stack

No specific products linked.