CVE-2026-127090
Jadaptive Maverick Synergy Server before 3.0.33 and 3.1.x before 3.1.7, and Maverick Legacy Server before 1.8.1, SSH Public Key Cross-User Authentication Bypass
Jadaptive Maverick Synergy Server before 3.0.33 and 3.1.x before 3.1.7, and Maverick Legacy Server before 1.8.1, contain an authentication bypass vulnerability in SSH public key authentication that reuses cached key authorization decisions across usernames. Attackers holding a key authorized for one account can authenticate it, then send a signed SSH_MSG_USERAUTH_REQUEST with a different username on the same connection to log in as that account.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Maverick Synergy Server Jadaptive com.sshtools/maverick-synergy-server
maven |
≥ 0; < 3.0.33 (affected, semver) ≥ 3.1.0; < 3.1.7 (affected, semver) Other versions: unaffected |
CNA: VulnCheck |
| Maverick Legacy Server Jadaptive |
≥ 0; < 1.8.1 (affected, semver)
Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 8.7 high |
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 8.8 high |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | CNA: VulnCheck |
| 4.0 / 8.7 high |
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD: [email protected] |
| 3.1 / 8.8 high |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://jadaptive.com/security/advisories/JADAPTIVE-SA-2026-001CNA: VulnCheck · vendor-advisory
- https://github.com/sshtools/maverick-synergy/commit/f7d23182cce985e21048215e96395881295cb0bdCNA: VulnCheck · patch
- https://store.jadaptive.com/app/api/releases/changes/01d04a39-0f05-4bae-842e-d2f1acc16985CNA: VulnCheck · release-notes
- https://store.jadaptive.com/app/api/releases/changes/ff71bdcf-a2a2-47e0-af5a-22e15af1dfa4CNA: VulnCheck · release-notes
- https://github.com/sshtools/maverick-synergy/blob/3.1.4/maverick-base/src/main/java/com/sshtools/common/auth/PublicKeyAuthentication.java#L82-L100CNA: VulnCheck · technical-description
- https://github.com/sshtools/maverick-synergy/blob/3.1.4/maverick-synergy-server/src/main/java/com/sshtools/server/AuthenticationProtocolServer.java#L185-L200CNA: VulnCheck · technical-description
- https://www.vulncheck.com/advisories/jadaptive-maverick-synergy-server-before-3.0.33-and-3.1-x-before-3.1.7-and-maverick-legacy-server-before-1.8.1-ssh-public-key-cross-user-authentication-bypassCNA: VulnCheck · third-party-advisory
- https://github.com/sshtools/maverick-synergy/blob/3.1.4/maverick-base/src/main/java/com/sshtools/common/auth/PublicKeyAuthentication.java#L82-L100[email protected]
- https://github.com/sshtools/maverick-synergy/blob/3.1.4/maverick-synergy-server/src/main/java/com/sshtools/server/AuthenticationProtocolServer.java#L185-L200[email protected]
- https://github.com/sshtools/maverick-synergy/commit/f7d23182cce985e21048215e96395881295cb0bd[email protected]
- https://jadaptive.com/security/advisories/JADAPTIVE-SA-2026-001[email protected]
- https://store.jadaptive.com/app/api/releases/changes/01d04a39-0f05-4bae-842e-d2f1acc16985[email protected]
- https://store.jadaptive.com/app/api/releases/changes/ff71bdcf-a2a2-47e0-af5a-22e15af1dfa4[email protected]
- https://www.vulncheck.com/advisories/jadaptive-maverick-synergy-server-before-3.0.33-and-3.1-x-before-3.1.7-and-maverick-legacy-server-before-1.8.1-ssh-public-key-cross-user-authentication-bypass[email protected]
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