CVE-2025-43857
published 2025-04-28CVE-2025-43857: 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…
PriorityP432medium6.5CVSS 3.1
AVNACLPRNUIRSUCNINAH
EPSS
0.41%
32.6th percentile
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.
Affected
18 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | ruby3.1 | — | — |
| debian | ruby3.3 | — | — |
| msrc | azl3_kernel_6.6.64.2-9_on_azure_linux_3.0 | — | — |
| msrc | azl3_kernel_6.6.92.2-1_on_azure_linux_3.0 | — | — |
| msrc | azl3_ruby_3.3.5-6_on_azure_linux_3.0 | — | — |
| msrc | cbl2_ruby_3.1.7-3_on_cbl_mariner_2.0 | — | — |
| ruby-lang | net | < 0.2.5 | 0.2.5 |
| ruby-lang | net | >= 0.3.0 < 0.3.9 | 0.3.9 |
| ruby-lang | net | >= 0.4.0 < 0.4.20 | 0.4.20 |
| ruby-lang | net | >= 0.5.0 < 0.5.7 | 0.5.7 |
| ruby | net-imap | — | — |
| ruby | net-imap | — | — |
| ruby | net-imap | — | — |
| ruby | net-imap | — | — |
| ruby | net-imap | >= 0 < 0.2.5 | 0.2.5 |
| ruby | net-imap | >= 0.3.0 < 0.3.9 | 0.3.9 |
| ruby | net-imap | >= 0.4.0 < 0.4.20 | 0.4.20 |
| ruby | net-imap | >= 0.5.0 < 0.5.7 | 0.5.7 |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
nvdv4.06.0MEDIUMCVSS: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
osv6.0MEDIUM
vendor_msrc6.5MEDIUM
vendor_debian6.0MEDIUM
vendor_redhat6.0MEDIUM
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Red Hat
net-imap: net-imap rubygem vulnerable to possible DoS by memory exhaustion
vendor_redhat·2025-04-28·CVSS 6.0
CVE-2025-43857 [MEDIUM] CWE-770 net-imap: net-imap rubygem vulnerable to possible DoS by memory exhaustion
net-imap: net-imap rubygem vulnerable to possible DoS by memory exhaustion
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 t
Microsoft
net-imap rubygem vulnerable to possible DoS by memory exhaustion
vendor_msrc·2025-04-08·CVSS 6.5
CVE-2025-43857 [MEDIUM] CWE-400 net-imap rubygem vulnerable to possible DoS by memory exhaustion
net-imap rubygem vulnerable to possible DoS by memory exhaustion
Mariner: Mariner
GitHub_M: GitHub_M
Customer Action Required: Yes
Debian
CVE-2025-43857: ruby3.1 - Net::IMAP implements Internet Message Access Protocol (IMAP) client functionalit...
vendor_debian·2025·CVSS 6.0
CVE-2025-43857 [MEDIUM] CVE-2025-43857: ruby3.1 - Net::IMAP implements Internet Message Access Protocol (IMAP) client functionalit...
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,
Microsoft
f2fs: fix null reference error when checking end of zone
vendor_msrc·2024-08-13·CVSS 5.5
CVE-2024-43857 [MEDIUM] CWE-476 f2fs: fix null reference error when checking end of zone
f2fs: fix null reference error when checking end of zone
FAQ: Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability?
One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.
Mariner: Mariner
Linux: Linux
Customer Action Required: Yes
Remediation: CBL-Mariner Releases
Reference: https://lear
OSV
net-imap rubygem vulnerable to possible DoS by memory exhaustion
osv·2025-04-28
CVE-2025-43857 [MEDIUM] net-imap rubygem vulnerable to possible DoS by memory exhaustion
net-imap rubygem vulnerable to possible DoS by memory exhaustion
### Summary
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).
### Details
The IMAP protocol allows "literal" strings to be sent in responses, prefixed with their size
GHSA
net-imap rubygem vulnerable to possible DoS by memory exhaustion
ghsa·2025-04-28
CVE-2025-43857 [MEDIUM] CWE-400 net-imap rubygem vulnerable to possible DoS by memory exhaustion
net-imap rubygem vulnerable to possible DoS by memory exhaustion
### Summary
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).
### Details
The IMAP protocol allows "literal" strings to be sent in responses, prefixed with their size
OSV
CVE-2025-43857: Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby
osv·2025-04-28·CVSS 6.0
CVE-2025-43857 [MEDIUM] CVE-2025-43857: Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby
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,
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
https://github.com/ruby/net-imap/pull/442https://github.com/ruby/net-imap/pull/444/commits/0ae8576c1a90bcd9573f81bdad4b4b824642d105#diff-53721cb4d9c3fb86b95cc8476ca2df90968ad8c481645220c607034399151462https://github.com/ruby/net-imap/pull/445https://github.com/ruby/net-imap/pull/446https://github.com/ruby/net-imap/pull/447https://github.com/ruby/net-imap/security/advisories/GHSA-j3g3-5qv5-52mj
2025-04-28
Published