CVE-2023-27556

Service interruption via Slowloris connection exhaustion

Published Apr 28, 2023 · Updated Jan 30, 2025

Slowloris denial of service in IBM Safer Payments allows remote attackers to interrupt its API and MCI interfaces with slow connections. The interfaces retain incomplete connections without incoming-connection limits, allowing concurrent requests to exhaust connection-handling resources. The attacker needs network access to an enabled API or MCI endpoint; the documented consequence is service interruption, not data disclosure or modification.

CVSS severity6.5
Medium
EPSS probability1.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Slowloris denial of service in IBM Safer Payments allows remote attackers to interrupt its API and MCI interfaces with slow connections. The interfaces retain incomplete connections without incoming-connection limits, allowing concurrent requests to exhaust connection-handling resources. The attacker needs network access to an enabled API or MCI endpoint; the documented consequence is service interruption, not data disclosure or modification.

The record

CVE
CVE-2023-27556
Published
Apr 28, 2023
Updated
Jan 30, 2025
Vendor
IBM
Product
IBM Safer Payments
Classifications
CWE-770, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 30, 2025Record 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=6.1.0.00, 6.2.0.00, 6.5.0.00
  2. Affected versionversion=6.3.0.00 <=6.3.1.03
  3. Affected versionversion=6.4.0.00 <=6.4.2.02

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

IBM · IBM Safer Paymentsversion=6.1.0.00, 6.2.0.00, 6.5.0.00; version=6.3.0.00 <=6.3.1.03; version=6.4.0.00 <=6.4.2.02

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.5IBM CorporationCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499Endpoint Denial of Service

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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