CVE-2023-31136Network attack vector

False query responses via buffered pre-TLS bytes

Published May 9, 2023 · Updated Jan 28, 2025

Improper TLS message handling in Vapor PostgresNIO before 1.14.2 allows man-in-the-middle attackers to inject false query responses. The connection state machine accepted bytes buffered after the server's one-byte SSL response and later processed them as trusted PostgreSQL messages. Exploitation requires interception of a TLS-enabled database connection; additional server and authentication conditions can expose passwords or other early-session data.

CVSS severity5.9
Medium
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper TLS message handling in Vapor PostgresNIO before 1.14.2 allows man-in-the-middle attackers to inject false query responses. The connection state machine accepted bytes buffered after the server's one-byte SSL response and later processed them as trusted PostgreSQL messages. Exploitation requires interception of a TLS-enabled database connection; additional server and authentication conditions can expose passwords or other early-session data.

The record

CVE
CVE-2023-31136
Published
May 9, 2023
Updated
Jan 28, 2025
Vendor
Vapor
Product
PostgresNIO
Classifications
CWE-924, CWE-349, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 9, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 28, 2025Record 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=< 1.14.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Vapor · PostgresNIOversion=< 1.14.2

Published CVSS scores

5.9GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
5.9NIST NVDCVSS: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-924Improper Enforcement of Message Integrity During Transmission in a Communication Channel
CWE-349Acceptance of Extraneous Untrusted Data With Trusted Data
T1557Adversary-in-the-Middle

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

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Your stack

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