CVE-2025-15367Network attack vector

POP3 command injection via unchecked control characters

Published Jan 20, 2026 · Updated Jan 20, 2026

Command injection in CPython poplib before 3.15.0a6 allows attackers to append POP3 commands through newline-bearing arguments. The poplib._putcmd method encodes each supplied command and passes it to _putline without rejecting CR, LF, or other control bytes. Reachability requires an application to pass attacker-controlled values after a privileged POP3 session is established; injected commands can read or alter mailbox data.

CVSS severity5.9
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Command injection in CPython poplib before 3.15.0a6 allows attackers to append POP3 commands through newline-bearing arguments. The poplib._putcmd method encodes each supplied command and passes it to _putline without rejecting CR, LF, or other control bytes. Reachability requires an application to pass attacker-controlled values after a privileged POP3 session is established; injected commands can read or alter mailbox data.

The record

CVE
CVE-2025-15367
Published
Jan 20, 2026
Updated
Jan 20, 2026
Vendor
Python Software Foundation
Product
CPython
Classifications
CWE-77
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Jan 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.15.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Python Software Foundation · CPythonversion=0 <3.15.0

Published CVSS scores

5.9Python Software FoundationCVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo