CVE-2023-52556 — In OpenBSD 7

In OpenBSD 7.4 before errata 009, a race condition between pf(4)'s processing of packets and expiration of packet states may cause a kernel panic.

01What is this vulnerability?

In OpenBSD 7.4 before errata 009, a race condition between pf(4)'s processing of packets and expiration of packet states may cause a kernel panic.

02Affected products

Vendor	Product	Versions
OpenBSD	OpenBSD	7.4

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: 2024-03-01T16:08:49.203Z
• Last modified: 2024-11-14T19:47:00.394Z

09References

• ftp.openbsd.org — https://ftp.openbsd.org/pub/OpenBSD/patches/7.4/common/009_pf.patch.sig
• github.com — https://github.com/openbsd/src/commit/9d9f4dc6c833cb79d13f836581e3a781d06842e7