What is CVE-2026-45538?

CVE-2026-45538 is a critical-severity vulnerability in Opensips, classified under Stack-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-08-04.

How severe is CVE-2026-45538?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Opensips

CVE-2026-45538

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 routin…

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Opensips — versions <= 4.0.0

Weakness classification (CWE)

CWE-121 — Stack-based Buffer Overflow

References

security-advisories@github.com (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-45538?: CVE-2026-45538 is a critical-severity vulnerability in Opensips, classified under Stack-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-08-04.
How severe is CVE-2026-45538?: Critical severity. CVSS v3 base score is 9.8 out of 10.