Dashboard / CVE-2026-27857

CVE-2026-27857

HIGH
MEDIUM Priority: 0.05 BB Relevance: 75/100
Published: 2026-03-27 Modified: 2026-10-26 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
S: Unchanged
C: None
I: None
A: High

Description

Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Install fixed version, there is no other remediation. No publicly available exploits are known.

Weakness Classification (2)

Affected Software (2)

VendorProductVersion
dovecot dovecot < 2.4.3
open-xchange dovecot < 2.3.22.1

References & Advisories (18)

Bug Bounty Relevance

75 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

CVSS Score

7.5 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploitation Probability

0.68%
Raw Score 0.006790
Percentile 52.3%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00679
2026-10-28
0.00679

Intelligence Sources

nvd ref →

External Links