CVE-2025-43857

MEDIUM EPSS 32.6%
Published Apr 28, 20251y ago · Modified Jun 17, 20261w ago
6.0 CVSS 4.0
Medium
Find Similar
Published Apr 28, 2025 1y ago
Last Modified Jun 17, 2026 1w ago

Description

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.5.7, 0.4.20, 0.3.9, and 0.2.5, there is a possibility for denial of service by memory exhaustion when net-imap reads server responses. At any time while the client is connected, a malicious server can send can send a "literal" byte count, which is automatically read by the client's receiver thread. The response reader immediately allocates memory for the number of bytes indicated by the server response. This should not be an issue when securely connecting to trusted IMAP servers that are well-behaved. It can affect insecure connections and buggy, untrusted, or compromised servers (for example, connecting to a user supplied hostname). This issue has been patched in versions 0.5.7, 0.4.20, 0.3.9, and 0.2.5.

CVSS Details

Base Score
6.0
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/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
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction P
Scope X

Threat Intelligence

EPSS Exploit Probability
32.6% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 4

CWE-400 Uncontrolled Resource Consumption Resource Mgmt
CWE-405
CWE-770
CWE-789

Affected Products 4

VendorProductVersionRange
ruby-langnet\\ <0.2.5
ruby-langnet\\≥0.3.0  –  <0.3.9
ruby-langnet\\≥0.4.0  –  <0.4.20
ruby-langnet\\≥0.5.0  –  <0.5.7

References 6

  • github.com https://github.com/ruby/net-imap/pull/442
    Issue TrackingPatch
  • github.com https://github.com/ruby/net-imap/pull/444/commits/0ae8576c1a90bcd9573f81bdad4b4b824642d105#diff-53721cb4d9c3fb86b95cc8476ca2df90968ad8c481645220c607034399151462
    Patch
  • github.com https://github.com/ruby/net-imap/pull/445
    Issue TrackingPatch
  • github.com https://github.com/ruby/net-imap/pull/446
    Issue TrackingPatch
  • github.com https://github.com/ruby/net-imap/pull/447
    Issue TrackingPatch
  • github.com https://github.com/ruby/net-imap/security/advisories/GHSA-j3g3-5qv5-52mj
    Vendor Advisory

Remediation

  • github.com https://github.com/ruby/net-imap/pull/442
    Issue TrackingPatch
  • github.com https://github.com/ruby/net-imap/pull/444/commits/0ae8576c1a90bcd9573f81bdad4b4b824642d105#diff-53721cb4d9c3fb86b95cc8476ca2df90968ad8c481645220c607034399151462
    Patch
  • github.com https://github.com/ruby/net-imap/pull/445
    Issue TrackingPatch
  • github.com https://github.com/ruby/net-imap/pull/446
    Issue TrackingPatch
  • github.com https://github.com/ruby/net-imap/pull/447
    Issue TrackingPatch