CVE-2021-0275

A Cross-site Scripting (XSS) vulnerability in J-Web on Juniper Networks Junos OS allows an attacker to target another user's session thereby gaining access to the users session. The other user session must be active for the attack to succeed. Once successful, the attacker has the same privileges as the user. If the user has root privileges, the attacker may be able to gain full control of the device. This issue affects: Juniper Networks Junos OS: 12.3 versions prior to 12.3R12-S15 on EX Series; 12.3X48 versions prior to 12.3X48-D95 on SRX Series; 15.1 versions prior to 15.1R7-S6 on EX Series; 15.1X49 versions prior to 15.1X49-D200 on SRX Series; 16.1 versions prior to 16.1R7-S7; 16.2 versions prior to 16.2R2-S11, 16.2R3; 17.1 versions prior to 17.1R2-S11, 17.1R3-S2; 17.2 versions prior to 17.2R3-S3; 17.3 versions prior to 17.3R2-S5, 17.3R3-S7; 17.4 versions prior to 17.4R2-S9, 17.4R3; 18.1 versions prior to 18.1R3-S9; 18.2 versions prior to 18.2R2-S7, 18.2R3-S3; 18.3 versions prior to 18.3R1-S7, 18.3R2-S3, 18.3R3-S1; 18.4 versions prior to 18.4R1-S6, 18.4R2-S4, 18.4R3; 19.1 versions prior to 19.1R2-S1, 19.1R3; 19.2 versions prior to 19.2R1-S3, 19.2R2; 19.3 versions prior to 19.3R2.

• CWE-79
• CWE-79

• https://kb.juniper.net/JSA11166Vendor Advisory
• https://kb.juniper.net/JSA11166Vendor Advisory

Published

Apr 22, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2021-0268An Improper Neutralization of CRLF Sequences in HTTP Headers…9.3
• CVE-2021-0269The improper handling of client-side parameters in J-Web of …8.8
• CVE-2021-0270On PTX Series and QFX10k Series devices with the "inline-jfl…5.9
• CVE-2021-0271A Double Free vulnerability in the software forwarding inter…6.5
• CVE-2021-0272A kernel memory leak in QFX10002-32Q, QFX10002-60C, QFX10002…6.5
• CVE-2021-0273An always-incorrect control flow implementation in the impli…5.3
• CVE-2021-0276A stack-based Buffer Overflow vulnerability in Juniper Netwo…9.8
• CVE-2021-0277An Out-of-bounds Read vulnerability in the processing of spe…8.8
• CVE-2021-0278An Improper Input Validation vulnerability in J-Web of Junip…7.8
• CVE-2021-0279Juniper Networks Contrail Cloud (CC) releases prior to 13.6.…5.5
• CVE-2021-0280Due to an Improper Initialization vulnerability in Juniper N…7.5
• CVE-2021-0281On Juniper Networks Junos OS devices configured with BGP ori…7.5