CVE-2026-33790
Juniper Junos ≤ 21.2
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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:A/V:C/RE:M/U:AmberSummary
CVE-2026-33790 is a high-severity Improper Check for Unusual or Exceptional Conditions (CWE-754) vulnerability in Juniper Junos. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Service Stop (T1489); ranked at the 26th 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 SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — 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-2026-33790 is an Improper Check for Unusual or Exceptional Conditions vulnerability (CWE-754) in the flow daemon (flowd) of Juniper Networks Junos OS on SRX Series devices. The issue occurs during NAT64 translation when the device receives a specific malformed ICMPv6 packet destined to it, causing the srxpfe process to crash and restart. This vulnerability cannot be triggered using IPv4 traffic or other types of IPv6 traffic. It affects Junos OS on SRX Series across multiple versions, including all versions prior to 21.2R3-S10, all 21.3 versions, 21.4 prior to 21.4R3-S12, all 22.1 versions, 22.2 prior to 22.2R3-S8, all 22.4 versions prior to 22.4R3-S9, 23.2 prior to 23.2R2-S6, 23.4 prior to 23.4R2-S7, 24.2 prior to 24.2R2-S3, 24.4 prior to 24.4R2-S3, and 25.2 prior to 25.2R1-S2 or 25.2R2.
A network-accessible attacker with no privileges required can exploit this vulnerability by sending the malformed ICMPv6 packet to a vulnerable SRX Series device performing NAT64 translation. A single packet triggers an srxpfe process crash and restart, while continued transmission of such packets sustains a denial-of-service condition by repeatedly crashing the process. The vulnerability has a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), indicating high availability impact with low complexity and no user interaction needed.
The Juniper security advisory at https://kb.juniper.net/JSA107874 provides details on affected versions and recommended patches, such as upgrading to fixed releases like 21.2R3-S10 and later where applicable. Security practitioners should consult this advisory for precise mitigation steps and verification procedures.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-21206
Vulnerability Data
An Improper Check for Unusual or Exceptional Conditions vulnerability in the flow daemon (flowd) of Juniper Networks Junos OS on SRX Series allows an attacker sending a specific, malformed ICMPv6 packet to cause the srxpfe process to crash and restart.…
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Continued receipt and processing of these packets will repeatedly crash the srxpfe process and sustain the Denial of Service (DoS) condition. During NAT64 translation, receipt of a specific, malformed ICMPv6 packet destined to the device will cause the srxpfe process to crash and restart. This issue cannot be triggered using IPv4 nor other IPv6 traffic. This issue affects Junos OS on SRX Series: * all versions before 21.2R3-S10, * all versions of 21.3, * from 21.4 before 21.4R3-S12, * all versions of 22.1, * from 22.2 before 22.2R3-S8, * all versions of 22.4, * from 22.4 before 22.4R3-S9, * from 23.2 before 23.2R2-S6, * from 23.4 before 23.4R2-S7, * from 24.2 before 24.2R2-S3, * from 24.4 before 24.4R2-S3, * from 25.2 before 25.2R1-S2, 25.2R2.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 7 hardening rules · 2 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation explicitly exercises unusual conditions to find missing or incorrect checks.
Input validation directly requires checking for unexpected or malformed conditions before they propagate.
Security engineering principles include structured handling of edge cases and exceptions during design.
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.
Secure development practices directly require proper checks and handling for exceptional conditions throughout the SDLC.
Runtime monitoring of software and environments can detect adverse events triggered by unhandled exceptional conditions.
Generating logs of exceptions and errors enables detection of improper handling of unusual conditions.
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.
Security testing in development and acceptance verifies handling of error and exceptional conditions.
Logging can record unhandled exceptions but does not prevent the weakness itself.
Monitoring may detect symptoms of unhandled conditions but does not eliminate the root weakness.
Secure development life cycle mandates exception handling and input validation that directly prevent missing checks for unusual conditions.
Application security requirements explicitly call for handling of exceptional conditions and error paths.
Secure system architecture and engineering principles require robust error and exception handling mechanisms.
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-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-754
- V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-754
Oracle Linux 9 (1 rule)
- V-271452 OL 9 must use a Linux Security Module configured to enforce limits on system services. prevents CWE-754