CVE-2021-23222Network attack vector

Query-response injection via buffered plaintext bytes

Published Mar 2, 2022 · Updated Aug 3, 2024

Improper input validation in libpq 9.6 through 14 allows man-in-the-middle attackers to inject false responses into early client queries. The socket reader retains bytes received with the server's encryption reply, then treats them as decrypted after SSL or GSS setup. Exploitation requires control of the TCP path; confidential-data exfiltration additionally requires a specially configured vulnerable server and later server access.

CVSS severity3.7
Low
EPSS probability1.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in libpq 9.6 through 14 allows man-in-the-middle attackers to inject false responses into early client queries. The socket reader retains bytes received with the server's encryption reply, then treats them as decrypted after SSL or GSS setup. Exploitation requires control of the TCP path; confidential-data exfiltration additionally requires a specially configured vulnerable server and later server access.

The record

CVE
CVE-2021-23222
Published
Mar 2, 2022
Updated
Aug 3, 2024
Vendor
PostgreSQL Global Development Group
Product
libpq
Classifications
CWE-522, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 2, 2022CVE 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=Affects v9.6 to v14

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PostgreSQL Global Development Group · libpqversion=Affects v9.6 to v14

Published CVSS scores

3.7PostgreSQL Global Development GroupCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
5.9NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-522Insufficiently Protected Credentials
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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