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Fencer Vulns
medium 5.8

CVE-2026-55706 json

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 4 mo ago modified 2026-07-13 3 mo ago also EUVD-2026-37521

cvss
5.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

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

Patch / fix

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • openwall.com https://www.openwall.com/lists/oss-security/2026/06/16/9 referenced PoC, tagged "exploit" by a source, unverified
  • blog.argus-systems.ai https://blog.argus-systems.ai/blog/poc-001-pap-bypass.py referenced PoC, tagged "exploit" by a source, unverified
  • blog.argus-systems.ai https://blog.argus-systems.ai/blog/openbsd-pap-27-year-auth-bypass.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.8 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L
NVD 3.1 8.3 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected products

  • OpenBSD OpenBSD

Classification

Weakness
  • CWE-1284 Improper Validation of Specified Quantity in Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.