CVE-2025-43857
net-imap rubygem vulnerable to possible DoS by memory exhaustion
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Timeline
ID reserved
By GitHub_M
- 11 days later
· 11 days later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | Medium6.0 | 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 |
| NVDNVD · Analyzed | 4.0 | Medium6.0 | 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 |
- EPSS (exploitation in 30 days)
- 0.49% · top 57% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.0.
Weakness
- CWE-400: Uncontrolled Resource Consumption (opens in a new tab)All about CWE-400 and its CVEs
- CWE-770: Allocation of Resources Without Limits or Throttling (opens in a new tab)All about CWE-770 and its CVEs
- CWE-789: Memory Allocation with Excessive Size Value (opens in a new tab)All about CWE-789 and its CVEs
- CWE-405: Asymmetric Resource Consumption (Amplification) (opens in a new tab)All about CWE-405 and its CVEs
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- RubyGemsnet-imapGHSA-j3g3-5qv5-52mj (opens in a new tab)
References (6)
- https://github.com/ruby/net-imap/security/advisories/GHSA-j3g3-5qv5-52mj (opens in a new tab)x_refsource_CONFIRM
- https://github.com/ruby/net-imap/pull/442 (opens in a new tab)x_refsource_MISC
- https://github.com/ruby/net-imap/pull/444/commits/0ae8576c1a90bcd9573f81bdad4b4b824642d105#diff-53721cb4d9c3fb86b95cc8476ca2df90968ad8c481645220c607034399151462 (opens in a new tab)x_refsource_MISC
- https://github.com/ruby/net-imap/pull/445 (opens in a new tab)x_refsource_MISC
- https://github.com/ruby/net-imap/pull/446 (opens in a new tab)x_refsource_MISC
- https://github.com/ruby/net-imap/pull/447 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-j3g3-5qv5-52mj (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2025-43857)Record last updated .