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CVE-2026-121944

sngrep through 1.9.0 Infinite Loop DoS via Crafted NFLOG TLV

6.8 Medium

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.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
None
User interaction
Passive

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.24%Unchanged since Nov 5, 2026
90%50%10%1%

What each source reports

CVE List Score used 6.8

sngrep through 1.9.0 Infinite Loop DoS via Crafted NFLOG TLV

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.

Record
CVE-2026-121944
CVSS 4.0
6.8 MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-835
Updated
2026-11-04
EUVDEUVD-2026-116901 6.8

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.

Record
EUVD-2026-116901
CVSS 4.0
6.8 MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Updated
2026-11-04
GitHub AdvisoriesGHSA-5wr4-785p-23qx 6.8

sngrep through 1.9.0 contains an infinite loop vulnerability in capture_packet_reasm_ip() in src...

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.

Record
GHSA-5wr4-785p-23qx
CVSS 4.0
6.8 MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-835
Updated
2026-11-04
NVD 6.8

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.

Record
CVE-2026-121944
CVSS 4.0
6.8 MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-835
Updated
2026-11-04
OSV 6.8

sngrep through 1.9.0 Infinite Loop DoS via Crafted NFLOG TLV

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.

Record
CVE-2026-121944
CVSS 4.0
6.8 MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness
CWE-835
Updated
2026-11-05
OSVDEBIAN-CVE-2026-121944 6.8

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.

Record
DEBIAN-CVE-2026-121944
CVSS 4.0
6.8 MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Updated
2026-11-07
OSVUBUNTU-CVE-2026-121944 6.8

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.

Record
UBUNTU-CVE-2026-121944
CVSS 4.0
6.8 MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-06

Affected products

Affected packages

Affected packages
PackageAffectedFixed
sngrep
Debian:12
 All versions, plus listed versions
1.6.0-11.7.0-11.7.0-21.7.0-2~bpo12+11.8.0-1
Show 9 moreShow less
1.8.1-11.8.2-11.8.2-1~bpo12+11.8.3-11.8.3-1~bpo13+11.8.4-11.8.4-1~bpo13+11.8.4-21.9.0-1
 None known
sngrep
Debian:13
 All versions, plus listed versions
1.8.2-11.8.3-11.8.3-1~bpo13+11.8.4-11.8.4-1~bpo13+11.8.4-21.9.0-1
 None known
sngrep
Debian:14
 All versions, plus listed versions
1.8.2-11.8.3-11.8.3-1~bpo13+11.8.4-11.8.4-1~bpo13+11.8.4-21.9.0-1
 None known
sngrep
Ubuntu:16.04:LTS
 All versions, plus listed versions
0.4.1-11.0.0-11.1.0-11.2.0-11.2.0-1build1
 None known
sngrep
Ubuntu:18.04:LTS
 All versions, plus listed versions
1.4.3-11.4.4-11.4.4-21.4.5-1
 None known
sngrep
Ubuntu:20.04:LTS
 All versions, plus listed versions
1.4.6-11.4.6-2
 None known
sngrep
Ubuntu:22.04:LTS
 All versions, plus listed versions
1.4.9-11.4.10-11.4.10-1ubuntu0.1
 None known
sngrep
Ubuntu:24.04:LTS
 All versions, plus listed versions
1.7.0-21.8.0-11.8.0-1build11.8.0-1build2
 None known
sngrep
Ubuntu:26.10
 All versions, plus listed versions
1.8.3-11.8.4-1
 None known
sngrep
Ubuntu:26.04:LTS
 All versions, plus listed versions
1.8.2-11.8.3-1
 None known

History

History
RecordedChangedSources
affected, aliases, referencesOSV
affected, aliases, published, referencesOSV
referencesEUVD, GitHub Advisories, NVD, OSV
referencesCVE List
publishedEUVD
publishedEUVD, NVD
aliases, referencesGitHub Advisories
cwes, references, severity, titleCVE List
first indexedEUVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-121944 is a medium vulnerability (CVSS 6.8) in Irontec Sngrep, published November 4, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.24%, the 14th percentile. No source names a fixed version.

References

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