CVE-2021-20199Public exploitNetwork attack vector

Remote trust bypass via loopback source rewriting

Published Feb 2, 2021 · Updated Aug 3, 2024

Origin validation error in Podman 1.8.0 through 2.2.1 allows remote attackers to access localhost-trusted container functionality. RootlessKit port forwarding supplies 127.0.0.1 as every inbound connection's source address instead of the slirp4netns device address. Exploitation requires a rootless container with a remotely published port and an application that grants unauthenticated localhost connections greater trust.

CVSS severity5.9
Medium
EPSS probability1.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin validation error in Podman 1.8.0 through 2.2.1 allows remote attackers to access localhost-trusted container functionality. RootlessKit port forwarding supplies 127.0.0.1 as every inbound connection's source address instead of the slirp4netns device address. Exploitation requires a rootless container with a remotely published port and an application that grants unauthenticated localhost connections greater trust.

The record

CVE
CVE-2021-20199
Published
Feb 2, 2021
Updated
Aug 3, 2024
Vendor
389 Directory Server
Product
Podman
Classifications
CWE-200, CWE-346, CAPEC-21, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=podman 1.8.0 onwards

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

389 Directory Server · Podmanversion=podman 1.8.0 onwards

Published CVSS scores

5.9NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
5.9Red HatCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A: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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
CWE-346Origin Validation Error
CAPEC-21Exploitation of Trusted Identifiers
T1190Exploit Public-Facing Application

Public exploit references

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

Technologies

Your stack

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Your stack

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