CVE intelligence and bounded remediation

CVE-2018-19518 — Php Php security vulnerability

High CVSS 8.5

University of Washington IMAP Toolkit 2007f on UNIX, as used in imap_open() in PHP and other products, launches an rsh command (by means of the imap_rimap function in c-client/imap4r1.c and the tcp_aopen function in osdep/unix/tcp_unix.c) without preventing argument injection, which might allow remote attackers to execute arbitrary OS commands if the IMAP server name is untrusted input (e.g., entered by a user of a web application) and if rsh has been replaced by a program with different argument semantics. For example, if rsh is a link to ssh (as seen on Debian and Ubuntu systems), then the attack can use an IMAP server name containing a "-oProxyCommand" argument.

Severity
High
CVSS
8.5 (2.0)
Published
2018-11-25
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-88

Affected products

  • php / php
  • debian / debian_linux / 8.0
  • debian / debian_linux / 9.0
  • uw-imap_project / uw-imap / 2007f
  • canonical / ubuntu_linux / 16.04
  • canonical / ubuntu_linux / 18.04

Showing 6 representative product identities from 10 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Command, code, expression, and template injection

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
  • Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
  • Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.

Remediate safely

  • Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
  • Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
  • Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.

Authoritative sources

Complete CVE record and remediation plan

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