TI-2020-18151 Aliases CVE-2020-35680 GHSA-924w-4qc7-pc84

smtpd/lka_filter.c in OpenSMTPD before 6.8.0p1, in certain configurations, allows remote…

LOW 39CWE-476Published 2020-12-24 · Updated 2024-08-04

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-476.

Summary

smtpd/lka_filter.c in OpenSMTPD before 6.8.0p1, in certain configurations, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted pattern of client activity, because the filter state machine does not properly maintain the I/O channel between the SMTP engine and the filters layer.

Why it matters now

EPSS 0.03652 89th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
—	—	all versions	—	No fix listed	CNA

— Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 5

CPE	Versions	Role	Vendor
cpe:2.3:a:opensmtpd:opensmtpd::::::::	before 6.8.0	Vulnerable	Opensmtpd
cpe:2.3:a:opensmtpd:opensmtpd:6.8.0:-::::::	6.8.0	Vulnerable	Opensmtpd
cpe:2.3:a:opensmtpd:opensmtpd:6.8.0:patch1-rc1::::::	6.8.0 patch1-rc1	Vulnerable	Opensmtpd
cpe:2.3:o:fedoraproject:fedora:32:::::::*	32	Vulnerable	Fedoraproject
cpe:2.3:o:fedoraproject:fedora:33:::::::*	33	Vulnerable	Fedoraproject

cpe:2.3:a:opensmtpd:opensmtpd:*:*:*:*:*:*:*:* Versions before 6.8.0 Vulnerable ·Opensmtpd
cpe:2.3:a:opensmtpd:opensmtpd:6.8.0:-:*:*:*:*:*:* Versions 6.8.0 Vulnerable ·Opensmtpd
cpe:2.3:a:opensmtpd:opensmtpd:6.8.0:patch1-rc1:*:*:*:*:*:* Versions 6.8.0 patch1-rc1 Vulnerable ·Opensmtpd
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product

Red Hat

Timeline

2026-10-02 Threatist record created from CVE-2020-35680
2026-10-03 Alias added: GHSA-924w-4qc7-pc84

References

Patch 1

https://github.com/openbsd/src/commit/6c3220444ed06b5796dedfd53a0f4becd903c0d1

Advisory 4

Other 1

https://www.mail-archive.com/misc%40opensmtpd.org/msg05188.html

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences