CVE-2026-121944 Details
Description
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.
A denial-of-service vulnerability has been identified in sngrep versions through 1.9.0. The issue arises from an infinite loop in the function capture_packet_reasm_ip() within src/capture.c. This loop is triggered by crafted NFLOG TLVs that cause the capture thread to consume full CPU resources, effectively halting packet processing. The vulnerability can be exploited by supplying a pcap file with a link type of NFLOG, containing a non-payload TLV with a length of less than 4. This flaw is distinct from a previously reported stack buffer overflow vulnerability in the same function, which was fixed in version 1.8.1.
Users can upgrade to sngrep version 1.9.1 or later, where this vulnerability has been addressed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Nov 4, 2026CISA-ADP
Assessed Nov 4, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://hackmd.io/@haindpwn/cve-2026-121943-121944-sngrep-sip-payload-missing-nul-oob-read | CISA-ADP | |
| https://github.com/irontec/sngrep/blob/v1.9.0/src/capture.c#L581-L598 | [email protected] | Source CodeVendor |
| https://github.com/irontec/sngrep/issues/589 | [email protected] | ExploitIssue TrackingTechnical AnalysisVendor |
| https://hackmd.io/@haindpwn/sngrep-sip-payload-missing-nul-oob-read | [email protected] | BundleExploitRemedyTechnical Analysis |
| https://www.vulncheck.com/advisories/sngrep-through-1.9.0-infinite-loop-dos-via-crafted-nflog-tlv | [email protected] | AdvisoryBundle |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-835 | Loop with Unreachable Exit Condition ('Infinite Loop') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| irontec sngrep | <= 1.9.0 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Nov 4, 2026 | CVE Modified | CISA-ADP |
| Nov 4, 2026 | New CVE Received | [email protected] |