Out-of-Bounds Stack Read in Irontec Sngrep Affects SIP Payload Processing
CVE-2026-121943

6.3MEDIUM

Key Information:

Vendor

Irontec

Status
Sngrep
Vendor
CVE Published:
4 November 2026

What is CVE-2026-121943?

The affected Irontec sngrep version, specifically 1.9.0, is vulnerable due to an out-of-bounds stack read occurring in the sip_check_packet and sip_validate_packet functions. This vulnerability stems from an off-by-one error in length checks on 10240-byte SIP payloads. Malicious remote attackers can exploit this flaw by crafting UDP or TCP SIP packets or by supplying specially designed pcap files, which may result in crashing the sngrep application or inadvertently leaking adjacent stack memory content into the displayed SIP fields.

Affected Version(s)

sngrep 0 <= 1.9.0

References

https://github.com/irontec/sngrep/issues/589
issue-tracking
https://hackmd.io/@haindpwn/sngrep-sip-payload-missing-nu...
third-party-advisory
https://github.com/irontec/sngrep/blob/v1.9.0/src/sip.c#L...
technical-description

CVSS V4

Score:
6.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
High
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

HaiND from the Post and Telecommunication Institute of Technology
.