Cyber Resilience

CVE-2026-33788

Access Control in Juniper Junos Os Evolved ≤ 21.2

Published
09 April 2026
Modified
22 July 2026
Patch / advisory
CVSS Score v4 8.5
Click a component to see what it means
Raw vectorCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:L/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:Y/R:U/V:X/RE:M/U:X
EPSS Score 0.0011 2th percentile
Risk Priority 30 floored blend · peak EPSS

Summary

CVE-2026-33788 is a high-severity Missing Authentication for Critical Function (CWE-306) vulnerability in Juniper Junos Os Evolved. Its CVSS base score is 8.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-14 (Permitted Actions Without Identification or Authentication) and IA-2 (Identification and Authentication (Organizational Users)) — 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.

CVE-2026-33788 is a Missing Authentication for Critical Function vulnerability (CWE-306) in the Flexible PIC Concentrators (FPCs) of Juniper Networks Junos OS Evolved on PTX Series routers. It affects PTX10004, PTX10008, and PTX10016 devices equipped with JNP10K-LC1201 or JNP10K-LC1202 line cards. Vulnerable versions include all releases prior to 21.2R3-S8-EVO; 21.4-EVO prior to 21.4R3-S7-EVO; 22.2-EVO prior to 22.2R3-S4-EVO; 22.3-EVO prior to 22.3R3-S3-EVO; 22.4-EVO prior to 22.4R3-S2-EVO; and 23.2-EVO prior to 23.2R2-EVO. The issue has a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), rated High.

A local, authenticated attacker with low privileges can exploit this vulnerability to gain direct access to the installed FPCs as a high-privileged user. This escalation can potentially lead to a full compromise of the affected FPC component.

Juniper's security advisory (JSA107806) details the vulnerability and recommends upgrading to one of the fixed releases listed above to mitigate the issue. Security practitioners should review the advisory for full patch details and verify configurations on affected PTX Series devices.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A Missing Authentication for Critical Function vulnerability in the Flexible PIC Concentrators (FPCs) of Juniper Networks Junos OS Evolved on PTX Series allows a local, authenticated attacker with low privileges to gain direct access to FPCs installed in the device.…

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A local user with low privileges can gain direct access to the installed FPCs as a high privileged user, which can potentially lead to a full compromise of the affected component. This issue affects Junos OS Evolved on PTX10004, PTX10008, PTX100016, with JNP10K-LC1201 or JNP10K-LC1202: * All versions before 21.2R3-S8-EVO, * 21.4-EVO versions before 21.4R3-S7-EVO, * 22.2-EVO versions before 22.2R3-S4-EVO, * 22.3-EVO versions before 22.3R3-S3-EVO, * 22.4-EVO versions before 22.4R3-S2-EVO, * 23.2-EVO versions before 23.2R2-EVO.

CWE(s)

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.
T1133 External Remote Services Persistence
Adversaries may leverage external-facing remote services to initially access and/or persist within a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-30391Same vendor: Juniper
CVE-2023-36851Same vendor: Juniper
CVE-2023-36846Same vendor: Juniper
CVE-2023-36847Same vendor: Juniper
CVE-2025-11198Same vendor: Juniper
CVE-2023-36833Same product: Juniper Junos Os Evolved
CVE-2024-21619Same vendor: Juniper
CVE-2024-47495Same product: Juniper Junos Os Evolved
CVE-2024-21598Same product: Juniper Junos Os Evolved
CVE-2024-39542Same product: Juniper Junos Os Evolved

Affected Assets

juniper
junos os evolved
21.2, 21.4, 22.2, 22.3, 22.4 · ≤ 21.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.2.3
  • V6.4.4
  • V10.4.16
  • V12.1.3

Mitigating Controls (NIST 800-53 r5) AI

Directly mandates unique identification and authentication of users before access to functions requiring identity.

Extends the same authentication requirement to non-organizational users accessing critical functionality.

Requires authentication of services before they can invoke or expose critical functions.

Explicitly identifies and limits actions permitted without authentication, preventing critical functions from being exposed.

Access enforcement requires prior authentication before any authorization decision for critical functions.

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

Directly requires authentication of users/services/hardware, which eliminates missing authentication for critical functions.

PR.AA-01 partial match
prevents

Managing identities and credentials is a prerequisite for authentication but does not itself enforce it on critical functions.

PR.AA-05 partial match
prevents

Defining and enforcing authorizations assumes prior authentication and therefore only partially mitigates the absence of authentication.

PR.IR-01 partial match
prevents

Protecting networks from unauthorized access can be undermined by missing authentication but does not address the root authentication gap.

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.

prevents

The control explicitly calls for authentication before any critical function is reached, eliminating the possibility of bypassing authentication for high-value operations.

prevents

Mandating authentication requirements for critical functions at the requirements-gathering stage ensures that essential operations are not left unprotected by missing login or verification mechanisms.

mitigates

Mandating authentication for network services and critical functions stops attackers from invoking sensitive operations without credentials, closing gaps where authentication is absent for important capabilities.

prevents

Security engineering principles insist on authentication and authorization for every critical function, eliminating entry points that lack any access control mechanism.

none

Requiring strong authentication and access-privilege enablement for remote connections ensures that critical functions cannot be invoked without proper verification, closing a gap that would otherwise allow unauthenticated use.

none

Mandatory use of access cards, biometrics, or two-factor authentication ensures that critical physical areas cannot be entered without proper authentication.

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-248585 OL 8 must require reauthentication when using the "sudo" command. prevents CWE-306
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-306
RHEL 7 (2 rules)
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-306
  • V-237635 The Red Hat Enterprise Linux operating system must require re-authentication when using the "sudo" command. prevents CWE-306
RHEL 8 (2 rules)
  • V-230492 RHEL 8 must not have the rsh-server package installed. prevents CWE-306
  • V-237643 RHEL 8 must require re-authentication when using the "sudo" command. prevents CWE-306

References