CVE-2026-129483

Description

Cyrus SASL through 2.1.28 contains an authentication bypass vulnerability in the SRP server mechanism because srp_server_mech_step2 does not reject client public values A that are multiples of N. Unauthenticated network clients can send A equal to N to force a zero shared secret, authenticating as any existing user without the password and learning session keys.

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

• 9.3CVSS 4.0, Criticalfrom the CNA (VulnCheck)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
• 9.1CVSS 3.1, Criticalfrom the CNA (VulnCheck)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

Timeline

1. 15 Nov 2026 Published

Weakness

• CWE-287

References

• github.comissue-tracking
• seclists.orgmailing-list
• gist.github.comexploit
• github.compatch
• github.comtechnical-description
• VulnCheck Advisory: Cyrus SASL through 2.1.28 SRP Authentication Bypass via plugins/srp.cthird-party-advisory