CVE-2023-29323 — ascii_load_sockaddr in smtpd in OpenBSD before 7

ascii_load_sockaddr in smtpd in OpenBSD before 7.1 errata 024 and 7.2 before errata 020, and OpenSMTPD Portable before 7.0.0-portable commit f748277, can abort upon a connection from a local, scoped IPv6 address.

01What is this vulnerability?

ascii_load_sockaddr in smtpd in OpenBSD before 7.1 errata 024 and 7.2 before errata 020, and OpenSMTPD Portable before 7.0.0-portable commit f748277, can abort upon a connection from a local, scoped IPv6 address.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-04-04T00:00:00.000Z
• Last modified: 2025-11-04T18:14:35.429Z

09References

• ftp.openbsd.org — https://ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/020_smtpd.patch.sig
• ftp.openbsd.org — https://ftp.openbsd.org/pub/OpenBSD/patches/7.1/common/024_smtpd.patch.sig
• cvsweb.openbsd.org — https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/smtpd/envelope.c.diff?r1=…
• cvsweb.openbsd.org — https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/smtpd/envelope.c.diff?r1=…
• cvsweb.openbsd.org — https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/smtpd/envelope.c.diff?r1=…
• github.com — https://github.com/OpenSMTPD/OpenSMTPD/commit/41d0eae481f538956b1f1fbadfb5350434…
• github.com — https://github.com/openbsd/src/commit/f748277ed1fc7065ae8998d61ed78b9ab1e55fae
• security.netapp.com — https://security.netapp.com/advisory/ntap-20230526-0006/
• lists.fedoraproject.org — https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro…