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CVE Record

CVE-2018-19518: University of Washington IMAP Toolkit 2007f on UNIX, as used in imap_open() in PHP and other products, laun...

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OS commands if the IMAP server name is untrusted input (e.g., entered by a user of a web application) and if rsh has been replaced by a program with different argument semantics.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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This issue can turn a user-supplied IMAP server name into unintended operating-system command execution on affected UNIX deployments. Business risk is concentrated in mail-related web applications that let users choose or enter IMAP server details, especially where PHP’s IMAP functions use the vulnerable UW IMAP toolkit behavior.

Executive priority

Prioritize remediation for internet-facing mail portals, helpdesk tools, or customer account systems that accept IMAP server details. For internally fixed mail hosts, urgency is lower but still warrants patch verification because public exploit material exists.

Technical view

UW IMAP Toolkit 2007f on UNIX can invoke rsh through imap_rimap and tcp_aopen without preventing argument injection. PHP imap_open() and other consumers may be exposed when the IMAP server name is untrusted input and rsh behaves like ssh, as documented for Debian and Ubuntu-style setups.

Likely exposure

Exposure is conditional, not universal. Look for UNIX systems using UW IMAP c-client or PHP IMAP where external users can influence the IMAP server name. Systems with fixed hostnames or no user-controlled IMAP configuration are less likely to be reachable.

Exploitation context

The bundle includes public exploit references and vendor advisories, but no CISA KEV listing and no cited evidence of active exploitation. The flaw requires a specific application data flow and local rsh behavior, so validation should focus on reachable user input paths.

Researcher notes

Key uncertainty is environmental: command execution depends on untrusted server-name input and rsh argument semantics. The CVE record names UW IMAP Toolkit 2007f on UNIX and PHP imap_open() usage, but the bundle does not provide a complete product/version matrix.

Mitigation direction

  • Apply relevant vendor security updates for UW IMAP, PHP IMAP, and distribution packages.
  • Check Debian, Ubuntu, Gentoo, NetApp, and PHP guidance for affected fixed package status.
  • Do not pass user-controlled IMAP server names directly to imap_open() or c-client consumers.
  • Restrict IMAP destinations to approved hostnames or centrally configured server profiles.
  • Review rsh replacement behavior on affected UNIX hosts, especially ssh-compatible implementations.

Validation and detection

  • Inventory applications using PHP imap_open() or UW IMAP c-client on UNIX.
  • Identify whether users can enter or modify IMAP server names.
  • Confirm installed packages include vendor fixes from applicable advisories.
  • Review application code for hostname allowlisting before IMAP connection creation.
  • Treat public proof-of-concept availability as a regression-test driver, not active exploitation evidence.
Prepared
Confidence
medium
Sources
11

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
19Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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