# CVE-2026-121943: Irontec sngrep through 1.9.0 Out-of-Bounds Stack Read via sip_check_packet

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- irontec / sngrep (irontec/sngrep): ≥ 0; ≤ 1.9.0 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- 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; source: CNA: VulnCheck

- 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; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-170

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/irontec/sngrep/issues/589 (CNA: VulnCheck; issue-tracking)

- https://hackmd.io/@haindpwn/sngrep-sip-payload-missing-nul-oob-read (CNA: VulnCheck; third-party-advisory)

- https://github.com/irontec/sngrep/blob/v1.9.0/src/sip.c#L396-L410 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/irontec-sngrep-through-1.9.0-out-of-bounds-stack-read-via-sip-check-packet (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-121943; retrieved 2026-11-04; source updated 2026-11-04

Revision: 27f88631bee5f0721cc6661fd48b48eb34a3928e59a667d60fb7dd55dc61debc

Canonical: https://y2.dev/cve/CVE-2026-121943

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