CVE-2023-27599Public exploitNetwork attack vector

Service crash via unterminated quoted To parameter

Published Mar 15, 2023 · Updated Feb 25, 2025

Improper input validation in OpenSIPS before 3.1.7 and 3.2.0 through 3.2.3 allows remote attackers to crash the SIP service. parse_to_param() fails to reject a quoted To-header parameter that reaches the end of the header, so append_hf() passes malformed state to anchor_lump(), whose consistency check calls abort(). The malformed SIP message is effective only when the routing configuration invokes affected code such as append_hf(), and the resulting process termination interrupts call signaling.

CVSS severity7.5
High
EPSS probability0.97%
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 OpenSIPS before 3.1.7 and 3.2.0 through 3.2.3 allows remote attackers to crash the SIP service. parse_to_param() fails to reject a quoted To-header parameter that reaches the end of the header, so append_hf() passes malformed state to anchor_lump(), whose consistency check calls abort(). The malformed SIP message is effective only when the routing configuration invokes affected code such as append_hf(), and the resulting process termination interrupts call signaling.

The record

CVE
CVE-2023-27599
Published
Mar 15, 2023
Updated
Feb 25, 2025
Vendor
OpenSIPS
Product
OpenSIPS
Classifications
CWE-20, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 15, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 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=< 3.1.7
  2. Affected versionversion=>= 3.2.0, < 3.2.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenSIPS · OpenSIPSversion=< 3.1.7; version=>= 3.2.0, < 3.2.4

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/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.

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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-20Improper Input Validation
T1499.004Application or System Exploitation

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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