CVE catalog

CVE-2025-43857

ruby3.1: CVE-2025-43857

Severity: Medium · CVSS 6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Published: Apr 28, 2025, 4:02:04 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.49% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	ruby3.1	bookworm	`3.1.2-7+deb12u1`	vulnerable
Debian	ruby3.1	bookworm-security	`3.1.2-7+deb12u1`	vulnerable
Alpine	ruby-net-imap	3.20	`0.4.22-r0`	fixed
Alpine	ruby-net-imap	3.21	`0.4.22-r0`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	ruby3.1	source	bookworm	`(unfixed)`	not yet assigned	Not reported	Not reported
Alpine	ruby-net-imap	apk	3.20	`0.4.22-r0`	Not reported	ALPINE-CVE-2025-43857	Not reported
Alpine	ruby-net-imap	apk	3.21	`0.4.22-r0`	Not reported	ALPINE-CVE-2025-43857	Not reported

Notes

[bookworm] ruby3.1: Minor issue

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libruby3.1]Affected
Source package: [ruby3.1]
Details (4)
- 3.1.2-7+deb12u1 · amd64 · bookworm
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · arm64 · bookworm
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · amd64 · bookworm-security
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · arm64 · bookworm-security
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
[ruby3.1]Affected
Details (4)
- 3.1.2-7+deb12u1 · amd64 · bookworm
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · arm64 · bookworm
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · amd64 · bookworm-security
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · arm64 · bookworm-security
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
[ruby3.1-dev]Affected
Source package: [ruby3.1]
Details (4)
- 3.1.2-7+deb12u1 · amd64 · bookworm
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · arm64 · bookworm
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · amd64 · bookworm-security
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · arm64 · bookworm-security
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
[ruby3.1-doc]Affected
Source package: [ruby3.1]
Details (4)
- 3.1.2-7+deb12u1 · all · bookworm
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · all · bookworm
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · all · bookworm-security
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12
- 3.1.2-7+deb12u1 · all · bookworm-security
  Affected
  dsa · ruby3.1 · debian · bookworm; dsa · ruby3.1 · debian · 12

[Debian 13 (Trixie)]

[libruby3.3]Affected
Source package: [ruby3.3]
Details (2)
- 3.3.8-2 · amd64 · trixie
  Affected
  dsa · ruby3.3 · debian · 13
- 3.3.8-2 · arm64 · trixie
  Affected
  dsa · ruby3.3 · debian · 13
[ruby3.3]Affected
Details (2)
- 3.3.8-2 · amd64 · trixie
  Affected
  dsa · ruby3.3 · debian · 13
- 3.3.8-2 · arm64 · trixie
  Affected
  dsa · ruby3.3 · debian · 13
[ruby3.3-dev]Affected
Source package: [ruby3.3]
Details (2)
- 3.3.8-2 · amd64 · trixie
  Affected
  dsa · ruby3.3 · debian · 13
- 3.3.8-2 · arm64 · trixie
  Affected
  dsa · ruby3.3 · debian · 13
[ruby3.3-doc]Affected
Source package: [ruby3.3]
Details (2)
- 3.3.8-2 · all · trixie
  Affected
  dsa · ruby3.3 · debian · 13
- 3.3.8-2 · all · trixie
  Affected
  dsa · ruby3.3 · debian · 13

Observed: Oct 24, 2026, 10:51:41 PM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]