# CVE-2026-90779: SIPp stack buffer overflow in createAuthHeader()

Source: https://junglewise.ai/threats/cve-2026-90779-sipp-stack-buffer-overflow-in-createauthheader  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-13. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-90779 · Severity: high · CVSS 7.5 · Published 2026-09-13

SIPp is a popular open-source SIP protocol testing tool used to simulate VoIP clients and servers. A malicious SIP server can send a specially crafted authentication challenge that causes a stack buffer overflow in SIPp's authentication handler, crashing the client and potentially allowing remote code execution. This affects organizations using SIPp for VoIP testing and quality assurance.

Technologies: [SIPp](https://junglewise.ai/threats/technologies/sipp). Vendors: [SIPp](https://junglewise.ai/threats/vendors/sipp).

## Quick answers

**Is CVE-2026-90779 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-90779 being exploited in the wild.

**How severe is CVE-2026-90779?** High severity, with a CVSS score of 7.5, published 13 September 2026.

**Which products and versions are affected?** SIPp through 3.7.7.

**Is there a fix for CVE-2026-90779?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-90779 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-90779?** Check whether you run SIPp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a stack buffer overflow in the createAuthHeader() function when processing SIP 401 or 407 authentication challenge responses. The flaw occurs when handling oversized algorithm parameters in SIP authentication challenges, allowing an attacker to corrupt stack memory. The attack vector is network-based and requires the victim to connect to a malicious SIP server that sends the crafted challenge. An attacker can trigger a denial of service (process crash) and potentially achieve remote code execution by overflowing the stack buffer with malicious data. The vulnerability affects SIPp through version 3.7.7.

## Affected products

- SIPp SIPp through 3.7.7

## Timeline

- 2026-09-13: disclosed: CVE-2026-90779 published

## References

- [https://github.com/SIPp/sipp](https://github.com/SIPp/sipp)
- [https://github.com/SIPp/sipp/blob/v3.7.7/src/auth.cpp](https://github.com/SIPp/sipp/blob/v3.7.7/src/auth.cpp)

## Related threats

- [SIPp buffer overflow in get_header function](https://junglewise.ai/threats/cve-2026-90780-sipp-buffer-overflow-in-get-header-function)
- [SIPp buffer overflow in get_peer_tag() function](https://junglewise.ai/threats/cve-2026-90778-sipp-buffer-overflow-in-get-peer-tag-function)
- [SIPp buffer overflow in command-line argument handling](https://junglewise.ai/threats/cve-2018-25356-sipp-buffer-overflow-in-command-line-argument-handling)