#VU108125 Resource exhaustion in net-imap - CVE-2025-43857

Vulnerability identifier: #VU108125

Vulnerability risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2025-43857

CWE-ID: CWE-400

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
net-imap
Universal components / Libraries / Libraries used by multiple products

Vendor: Ruby

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to application does not properly control consumption of internal resources when reading server responses. A malicious server can trigger resource exhaustion and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

net-imap: 0.2.0 - 0.2.4, 0.3.0 - 0.3.8, 0.4.0 - 0.4.19, 0.5.0 - 0.5.6

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External links
https://github.com/ruby/net-imap/pull/442
https://github.com/ruby/net-imap/pull/444/commits/0ae8576c1a90bcd9573f81bdad4b4b824642d105#diff-53721cb4d9c3fb86b95cc8476ca2df90968ad8c481645220c607034399151462
https://github.com/ruby/net-imap/pull/445
https://github.com/ruby/net-imap/pull/446
https://github.com/ruby/net-imap/pull/447
https://github.com/ruby/net-imap/security/advisories/GHSA-j3g3-5qv5-52mj
https://www.ruby-lang.org/en/news/2025/04/28/dos-net-imap-cve-2025-43857/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.