Net::IMAP: Command Injection via non-synchronizing literal in "raw" argument

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.8 · CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-47240: 0.83% estimated exploitation activity in the next 30 days; percentile 57.62 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Several Net::IMAP commands accept a "raw data" argument that is sent verbatim after validation to prevent command injection. However, if a server does not support non-synchronizing literals, it may still be possible to inject arbitrary IMAP commands inside non-synchronizing literals. Details Raw data arguments support embedded literal values, both synchronizing and non-synchronizing. Non-synchronizing literals can only be safely sent when the server advertises any of the LITERAL+, LITERAL-, or IMAP4rev2 capabilities. But raw data arguments do not verify server support for non-synchronizing literals prior to sending. Servers without support for non-synchronizing literals could handle them in several different ways: If a server sees a "}\r\n" byte sequence but can't parse the literal bytesize, it may cautiously decide to close the connection, blocking any command injection attacks. However, a server without support for non-synchronizing literals may instead interpret the "+}\r\n" as…

Published by the source

9 Jun 2026, 18:36 UTC

Last modified by the source

6 Jul 2026, 22:53 UTC

Source last checked

26 Oct 2026, 15:52 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-8p34-64r3-mwg8

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# Patch Next advisory brief: CVE-2026-47240

Advisory: Net::IMAP: Command Injection via non-synchronizing literal in "raw" argument
IDs: CVE-2026-47240, GHSA-8p34-64r3-mwg8
Record: https://patchnext.com/advisories/cve-2026-47240 (revision 1, source checked 26 Oct 2026, 15:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: net-imap 0.6.4.1, 0.5.15. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems net-imap: affected >= 0.6.0, <= 0.6.4; <= 0.5.14; fixed in 0.6.4.1, 0.5.15

## Suggested inspection (read-only)
- RubyGems net-imap: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on net-imap.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-8p34-64r3-mwg8 (GitHub-reviewed advisory GHSA-8p34-64r3-mwg8 lists affected ranges: RubyGems net-imap >=0.6.0 =0 <=0.5.14)

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