---
id: CVE-2026-121943
title: Irontec sngrep through 1.9.0 Out-of-Bounds Stack Read via sip_check_packet
summary: >-
  Irontec sngrep through 1.9.0 contains an out-of-bounds stack read
  vulnerability in sip_check_packet and sip_validate_packet caused by an
  off-by-one length check on 10240-byte SIP payloads. Remote attackers can send
  a crafted UDP or TCP S…
severity: medium
cvss: 4.8
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L'
cvssSource: cna
cwe:
  - CWE-170
vendor: irontec
product: sngrep
affected:
  - sngrep <= 1.9.0
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-04T18:51:33.759102Z'
exploitAvailable: true
published: '2026-11-04'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T18:51:59.965Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-121943'
references:
  - url: 'https://github.com/irontec/sngrep/issues/589'
  - url: 'https://hackmd.io/@haindpwn/sngrep-sip-payload-missing-nul-oob-read'
  - url: 'https://github.com/irontec/sngrep/blob/v1.9.0/src/sip.c#L396-L410'
  - url: >-
      https://www.vulncheck.com/advisories/irontec-sngrep-through-1.9.0-out-of-bounds-stack-read-via-sip-check-packet
    label: >-
      VulnCheck Advisory: Irontec sngrep through 1.9.0 Out-of-Bounds Stack Read
      via sip_check_packet
tags:
  - cve.org
  - exploit-available
ingestedAt: '2026-11-05T21:36:00.506Z'
epss: 0.05551
epssPercentile: 0.92893
---

## Overview

Irontec sngrep through 1.9.0 contains an out-of-bounds stack read vulnerability in sip_check_packet and sip_validate_packet caused by an off-by-one length check on 10240-byte SIP payloads. Remote attackers can send a crafted UDP or TCP SIP packet or supply a pcap file to crash sngrep or leak adjacent stack bytes into displayed SIP fields.

## Affected

- `sngrep <= 1.9.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.