Vulnerability-Lookup

CVE-2026-45538 (GCVE-0-2026-45538)

Vulnerability from cvelistv5 – Published: 2026-08-04 20:47 – Updated: 2026-08-05 14:28

Title

OpenSIPS: Stack Buffer Overflow in sip_to_json() Header Name Copy

Summary

OpenSIPS is a Session Initiation Protocol (SIP) server implementation. In versions 4.0.0 and prior, processing a SIP message with a header name longer than 255 bytes causes a stack buffer overflow when sip_to_json() is called in the routing script. Function sip_to_json() (modules/sipmsgops/sipmsgops.c) copies SIP header names into a fixed 255-byte stack buffer without bounds checking, performing a memcpy of the full header-name length even though the SIP parser imposes no such limit (a header name can be roughly 65000 bytes). As a result, when a routing script calls sip_to_json(), a SIP message with a header name longer than 255 bytes triggers a stack buffer overflow in which both the length and content of the overwrite are attacker-controlled, corrupting the saved frame pointer and return address. A single unauthenticated UDP packet to the SIP port (5060) can crash the process or, on builds without stack protections, hijack the return address to achieve remote code execution. This affects deployments whose routing script invokes sip_to_json(). This issue was not fixed at the time of publication.

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: poc Automatable: yes Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-121 - Stack-based Buffer Overflow

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/OpenSIPS/opensips/security/adv…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
OpenSIPS	opensips	Affected: <= 4.0.0

Show details on NVD website

JSON

To clipboard

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                "id": "CVE-2026-45538",
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          "value": "OpenSIPS is a Session Initiation Protocol (SIP) server implementation. In versions 4.0.0 and prior, processing a SIP message with a header name longer than 255 bytes causes a stack buffer overflow when sip_to_json() is called in the routing script. Function sip_to_json() (modules/sipmsgops/sipmsgops.c) copies SIP header names into a fixed 255-byte stack buffer without bounds checking, performing a memcpy of the full header-name length even though the SIP parser imposes no such limit (a header name can be roughly 65000 bytes). As a result, when a routing script calls sip_to_json(), a SIP message with a header name longer than 255 bytes triggers a stack buffer overflow in which both the length and content of the overwrite are attacker-controlled, corrupting the saved frame pointer and return address. A single unauthenticated UDP packet to the SIP port (5060) can crash the process or, on builds without stack protections, hijack the return address to achieve remote code execution. This affects deployments whose routing script invokes sip_to_json(). This issue was not fixed at the time of publication."
        }
      ],
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      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
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}

ubuntu-cve-2026-45538

Vulnerability from osv_ubuntu

Published

2026-08-04 21:16

Modified

2026-08-04 21:16

Summary

Details

Severity

9.8 (Critical)


                    
                      CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-45538	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-45538	REPORT
	https://github.com/OpenSIPS/opensips/security/adv…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "opensips",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-b2bua-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-berkeley-bin",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-berkeley-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-carrierroute-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-compression-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-console",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-cpl-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-dbhttp-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-dialplan-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-emergency-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-geoip-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-http-modules",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-identity-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-jabber-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-json-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-ldap-modules",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-lua-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-memcached-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-mysql-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-perl-modules",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-postgres-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-presence-modules",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-rabbitmq-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-radius-modules",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-redis-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-regex-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-restclient-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-sctp-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-snmpstats-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-sqlite-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-tls-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-tlsmgm-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-unixodbc-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-wss-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-xmlrpc-module",
            "binary_version": "2.2.2-3build4"
          },
          {
            "binary_name": "opensips-xmpp-module",
            "binary_version": "2.2.2-3build4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "opensips",
        "purl": "pkg:deb/ubuntu/opensips@2.2.2-3build4?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.2.2-3build2",
        "2.2.2-3build3",
        "2.2.2-3build4"
      ]
    }
  ],
  "aliases": [],
  "details": "OpenSIPS is a Session Initiation Protocol (SIP) server implementation. In versions 4.0.0 and prior, processing a SIP message with a header name longer than 255 bytes causes a stack buffer overflow when sip_to_json() is called in the routing script. Function sip_to_json() (modules/sipmsgops/sipmsgops.c) copies SIP header names into a fixed 255-byte stack buffer without bounds checking, performing a memcpy of the full header-name length even though the SIP parser imposes no such limit (a header name can be roughly 65000 bytes). As a result, when a routing script calls sip_to_json(), a SIP message with a header name longer than 255 bytes triggers a stack buffer overflow in which both the length and content of the overwrite are attacker-controlled, corrupting the saved frame pointer and return address. A single unauthenticated UDP packet to the SIP port (5060) can crash the process or, on builds without stack protections, hijack the return address to achieve remote code execution. This affects deployments whose routing script invokes sip_to_json(). This issue was not fixed at the time of publication.",
  "id": "UBUNTU-CVE-2026-45538",
  "modified": "2026-08-04T21:16:00Z",
  "published": "2026-08-04T21:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-45538"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-45538"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/OpenSIPS/opensips/security/advisories/GHSA-37wc-5j8j-95x3"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-45538"
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-45538 (GCVE-0-2026-45538)

ubuntu-cve-2026-45538

Vulnerability from osv_ubuntu

Tags

Sightings

Nomenclature