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CVE-2026-121943

6.3 mediumEPSS 5.6%

Medium (6.3) in irontec sngrep. EPSS 5.6% estimated probability of exploitation activity in the next 30 days.

On this page
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.

Severity

CVSS 4.0

6.3 medium
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS 3.1

4.8 medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
EPSS
5.6% estimated probability of exploitation activity in the next 30 days; 93rd percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
CISA's assessment (SSVC)
Exploitation: PoC · Automatable: no · Technical impact: partial, assessed 2026-11-04. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
CWE
CWE-170 Improper Null Termination
Published
Modified
NVD analysis
Deferred: the NVD does not plan to analyze it
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
irontec sngrepthrough 1.9.0

Linux distributions

DistributionReleasePackageFixed inAdvisory
Debian12, 13, 14sngrepno fix listedDEBIAN-CVE-2026-121943
Ubuntu16.04:LTS, 18.04:LTS, 20.04:LTS and 4 moresngrepno fix listedUBUNTU-CVE-2026-121943

From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.

Red Hat

Red Hat rates this Moderate.

Red Hat's statement

This vulnerability is rated as Moderate severity because exploitation requires an active capture session or manual processing of an untrusted capture file, limiting the blast radius to the diagnostic process without compromising underlying system integrity. Additionally, sngrep is an interactive command-line diagnostic tool rather than a continuously running system service, significantly reducing exposure on production environments. Red Hat does not package or distribute sngrep, and the issue primarily impacts community distributions such as Fedora when the tool is manually invoked.

Red Hat's mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Contains Red Hat Security Data © Red Hat, Inc., licensed under CC BY 4.0. Source: https://access.redhat.com/security/data. Modified: reformatted. Red Hat's page for CVE-2026-121943.

References

Check your stackJSON