CVE-2026-47241 — Net::IMAP: Denial of Service via incomplete raw argument validation

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, several Net::IMAP commands accept a raw string argument which is only validated to prevent CRLF injection and then sent verbatim. If this string is derived from user-controlled input, an attacker can force the next command to be absorbed as a continuation of the first command. This will cause the first command to eventually fail, but also prevents it from returning until another command is sent (from another thread). That other command will not return until the connection is closed. This vulnerability is fixed in 0.6.5 and 0.5.15.

Published Jun 22, 2026Updated Jun 23, 2026Sources: cvelistV5, GitHub_M

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

chance of exploitation in 30 days

Affects

ruby

net_imap

CVSS base

2.1

LOW

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

ruby

Products (1)

net imap

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
2.1	CVSS 4.0	LOW	—	—	cvelistV5

Weakness & attack patterns

CWE-162
CWE-182
CWE-186

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

T1036.007Masquerading: Double File Extension

References

1 on the record

github.com/ruby/net-imap/security/advisories/GHSA-c4fp-cxrr-mj66
x_refsource_CONFIRM

Elsewhere on this site

rubyevery CVE for this vendor
CWE-162other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.