---
id: CVE-2026-121944
title: sngrep through 1.9.0 Infinite Loop DoS via Crafted NFLOG TLV
summary: >-
  sngrep through 1.9.0 contains an infinite loop vulnerability in
  capture_packet_reasm_ip() in src/capture.c that allows attackers to cause
  denial of service via crafted NFLOG TLVs. Attackers can supply a pcap file
  with link type NFLOG con…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-835
vendor: irontec
product: sngrep
affected:
  - sngrep <= 1.9.0
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-04T18:50:54.265569Z'
exploitAvailable: true
published: '2026-11-04'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T18:51:15.773Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-121944'
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/capture.c#L581-L598'
  - url: >-
      https://www.vulncheck.com/advisories/sngrep-through-1.9.0-infinite-loop-dos-via-crafted-nflog-tlv
    label: >-
      VulnCheck Advisory: sngrep through 1.9.0 Infinite Loop DoS via Crafted
      NFLOG TLV
tags:
  - cve.org
  - exploit-available
ingestedAt: '2026-11-05T21:36:00.504Z'
epss: 0.00237
epssPercentile: 0.14832
---

## Overview

sngrep through 1.9.0 contains an infinite loop vulnerability in capture_packet_reasm_ip() in src/capture.c that allows attackers to cause denial of service via crafted NFLOG TLVs. Attackers can supply a pcap file with link type NFLOG containing a non-payload TLV with length under 4, making the capture thread spin at full CPU and stop processing packets.

## Affected

- `sngrep <= 1.9.0`

## Remediation

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