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TI-2020-16681 Aliases CVE-2020-27507GHSA-q52j-c5xj-88qf

The Kamailio SIP before 5.5.0 server mishandles INVITE requests with duplicated fields…

Priority HIGH 82CWE-120Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-120 and the CVSS impact.

Summary

The Kamailio SIP before 5.5.0 server mishandles INVITE requests with duplicated fields and overlength tag, leading to a buffer overflow that crashes the server or possibly have unspecified other impact.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.01176 67th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:kamailio:kamailio:*:*:*:*:*:*:*:*before 5.5.0Vulnerablekamailio
  • cpe:2.3:a:kamailio:kamailio:*:*:*:*:*:*:*:* Versions before 5.5.0 Vulnerable ·kamailio

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-27507
  2. 2026-10-03 Alias added: GHSA-q52j-c5xj-88qf

References

Exploit 1

Patch 1

Other 1

  • TI-2018-06372 A Buffer Overflow issue was discovered in Kamailio before 4.4.7, 5.0.x before 5.0.6, and… CVSS 3.0CRITICAL 9.8
  • TI-2018-10598 In Kamailio before 5.0.7 and 5.1.x before 5.1.4, a crafted SIP message with a double "To"… CVSS 3.0CRITICAL 9.8
  • TI-2016-02145 Heap-based buffer overflow in the encode_msg function in encode_msg.c in the SEAS module… CVSS 3.0CRITICAL 9.8
  • TI-2025-11190 Kamailio Grammar Rule cfg.y yyerror_at null pointer dereference CVSS 4.0MEDIUM 4.8
  • TI-2025-11189 Kamailio rvalue.c rve_is_constant null pointer dereference CVSS 4.0MEDIUM 4.8
  • TI-2025-11188 Kamailio Configuration File cfg.lex sr_push_yy_state use after free CVSS 4.0MEDIUM 4.8
See all 16 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences