What is CVE-2026-55706?

CVE-2026-55706 is a medium-severity vulnerability in OpenBSD, classified under Improper Validation of Specified Quantity in Input. CVSS score: 5.8/10. Published 2026-06-17.

How severe is CVE-2026-55706?

Medium severity. CVSS v3 base score is 5.8 out of 10.

Vulnerability in OpenBSD

CVE-2026-55706

sppp_pap_input in sys/net/if_spppsubr.c in OpenBSD before 076e2b1 allows authentication bypass via certain zero values for lengths.

Published 2026-06-17 · last modified 2026-07-13.

CVSS v3 metric

CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.003 (25.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.003 · change: -0.000

Affected products

OpenBSD — versions 0

Weakness classification (CWE)

CWE-1284 — Improper Validation of Specified Quantity in Input

References

blog.argus-systems.ai/blog/openbsd-pap-27-year-auth-bypass.html (Exploit, Third Party Advisory)
www.openwall.com/lists/oss-security/2026/06/16/9 (Exploit, Patch, Mailing List, Third Party Advisory)
github.com/openbsd/src/commit/076e2b1c1fc4ac0883a72d3544131ad5cee7adf8 (Patch)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (Exploit)

Frequently asked questions

What is CVE-2026-55706?: CVE-2026-55706 is a medium-severity vulnerability in OpenBSD, classified under Improper Validation of Specified Quantity in Input. CVSS score: 5.8/10. Published 2026-06-17.
How severe is CVE-2026-55706?: Medium severity. CVSS v3 base score is 5.8 out of 10.