Cyber Resilience

CVE-2025-34026

Auth Bypass in Versa-Networks Concerto 11.4.0 – 12.1.2

CISA KEVActive ExploitationEUVD ExploitedPublic PoCAuth Bypass
Published
21 May 2025
Modified
17 June 2026
KEV Added
22 January 2026
Patch / advisory
CVSS Score v4 9.2
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:L/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
EPSS Score 0.83 99.6th percentile
Risk Priority 75 floored blend · peak EPSS

Summary

CVE-2025-34026 is a critical-severity Authentication Bypass Using an Alternate Path or Channel (CWE-288) vulnerability in Versa-Networks Concerto. Its CVSS base score is 9.2 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 0.4% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-25 (Reference Monitor) and AC-3 (Access Enforcement) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

The Versa Concerto SD-WAN orchestration platform contains an authentication bypass vulnerability in its Traefik reverse proxy configuration, tracked as CVE-2025-34026 and assigned CWE-288. The flaw affects versions 12.1.2 through 12.2.0, with additional versions potentially impacted, and enables unauthenticated access to administrative endpoints including the internal Actuator, which exposes heap dumps and trace logs. The vulnerability carries a CVSS 4.0 score of 9.2 reflecting network attack vector, low complexity, and high confidentiality impact.

An unauthenticated remote attacker can exploit the bypass to reach protected administrative interfaces without credentials, obtaining sensitive runtime data such as heap dumps and trace logs that may contain credentials or other internal state. The attack requires no user interaction or privileges and can be performed over the network.

Versa Networks has published guidance via its security portal bulletin, while CISA includes the CVE in its Known Exploited Vulnerabilities catalog, indicating confirmed in-the-wild exploitation and recommending prompt remediation for affected deployments.

The EPSS score reached a peak of 0.7505 on 2026-03-26 and remains elevated at 0.7108, consistent with sustained exploitation interest following disclosure.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

The Versa Concerto SD-WAN orchestration platform is vulnerable to an authentication bypass in the Traefik reverse proxy configuration, allowing at attacker to access administrative endpoints. The internal Actuator endpoint can be leveraged for access to heap dumps and trace logs.This…

more

issue is known to affect Concerto from 12.1.2 through 12.2.0. Additional versions may be vulnerable.

CWE(s)
KEV Date Added
22 January 2026

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1542.002 Component Firmware Stealth
Adversaries may modify component firmware to persist on systems.
T1556 Modify Authentication Process Defense Impairment
Adversaries may modify authentication mechanisms and processes to access user credentials or enable otherwise unwarranted access to accounts.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-27198Shared CWE-288both on KEV
CVE-2025-4427Shared CWE-288both on KEV
CVE-2024-1709Shared CWE-288both on KEV
CVE-2026-24858Shared CWE-288both on KEV
CVE-2025-2746Shared CWE-288both on KEV
CVE-2025-24472Shared CWE-288both on KEV
CVE-2024-55591Shared CWE-288both on KEV
CVE-2026-18577Shared CWE-288both on KEV
CVE-2026-18556Shared CWE-288both on KEV
CVE-2026-23760Shared CWE-288both on KEV

Affected Assets

versa-networks
concerto
12.1.2, 12.2.0 · 11.4.0 — 12.1.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 7 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.4.3
  • V6.6.1
  • V12.1.3

Mitigating Controls (NIST 800-53 r5) AI

Requires a tamperproof, always-invoked reference monitor that structurally blocks bypass via any alternate path.

Enforces authorization checks on every logical access path, eliminating unauthenticated alternate channels.

Mandates unique identification and authentication for all organizational users, covering the primary authentication requirement.

Controls all external and key internal interfaces, reducing the chance of unauthenticated alternate channels.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 full match
prevents

Requiring authentication on every channel and path directly eliminates alternate-path bypasses.

PR.AA-05 mostly match
prevents

Enforcing authorizations and least privilege across all access vectors prevents unauthenticated alternate paths.

PR.IR-01 mostly match
prevents

Protecting networks and environments from unauthorized logical access blocks bypass via undocumented channels.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can detect alternate-path bypasses but does not prevent them in production.

degrades

Secure authentication control directly mitigates bypass by requiring strong, consistent authentication on all paths.

prevents

Access control policy directly addresses alternate authentication paths by requiring all channels to enforce authentication.

degrades

Authentication information management ensures credentials and mechanisms are consistently applied across all access paths.

prevents

Access rights provisioning and review prevent bypass via unmonitored or alternate channels.

prevents

Privileged access rights control reduces risk of bypass through elevated or alternate paths.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248598 There must be no ".shosts" files on the OL 8 operating system. prevents CWE-288
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-288
Oracle Linux 9 (2 rules)
  • V-271757 OL 9 file systems must not contain shosts.equiv files. prevents CWE-288
  • V-271758 OL 9 file systems must not contain .shosts files. prevents CWE-288
RHEL 7 (3 rules)
  • V-204440 Red Hat Enterprise Linux operating systems version 7.2 or newer using Unified Extensible Firmware Interface (UEFI) must require authentication upon booting into single-user and maintenance modes. prevents CWE-288
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-288
  • V-204424 The Red Hat Enterprise Linux operating system must not allow accounts configured with blank or null passwords. prevents CWE-288

References