CVE-2021-0268

An Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting') weakness in J-web of Juniper Networks Junos OS leads to buffer overflows, segment faults, or other impacts, which allows an attacker to modify the integrity of the device and exfiltration information from the device without authentication. The weakness can be exploited to facilitate cross-site scripting (XSS), cookie manipulation (modifying session cookies, stealing cookies) and more. This weakness can also be exploited by directing a user to a seemingly legitimate link from the affected site. The attacker requires no special access or permissions to the device to carry out such attacks. This issue affects: Juniper Networks Junos OS: 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S5; 18.3 versions prior to 18.3R2-S4, 18.3R3-S3; 18.4 versions prior to 18.4R2-S5, 18.4R3-S3; 19.1 versions prior to 19.1R2-S2, 19.1R3-S2; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2, 19.4R3; 20.1 versions prior to 20.1R1-S2, 20.1R2. This issue does not affect Juniper Networks Junos OS versions prior to 18.1R1.

• CWE-79
• CWE-113
• CWE-120
• CWE-74

• https://kb.juniper.net/JSA11159Vendor Advisory
• https://kb.juniper.net/JSA11159Vendor Advisory

Published

Apr 22, 2021

Last Modified

Jun 17, 2026

Status

Modified

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• CVE-2021-0269The improper handling of client-side parameters in J-Web of …8.8
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• 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-2021-0275A Cross-site Scripting (XSS) vulnerability in J-Web on Junip…8.8