ET WEB_SPECIFIC_APPS Atlassian Unauthenticated Arbitrary File Read (CVE-2026-21589)

Query · suricata

flow:established,to_server;
http.uri;
content:"/download/resources/";
pcre:"/^.*?(?:(?:\x2e|%(?:25)*2[Ee]){1,2}(?:\x2f|\x5c|\x3a{2}|%(?:25)*5[Cc]|%(?:25)*2[Ff]|%(?:25)*3[aA]){1,}){2,}/R";
target:dest_ip;
Raw source ET WEB_SPECIFIC_APPS Atlassian Unauthenticated Arbitrary File Read (CVE-2026-21589) · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (
    msg:"ET WEB_SPECIFIC_APPS Atlassian Unauthenticated Arbitrary File Read (CVE-2026-21589)";
    flow:established,to_server;
    http.uri;
    content:"/download/resources/";
    pcre:"/^.*?(?:(?:\x2e|%(?:25)*2[Ee]){1,2}(?:\x2f|\x5c|\x3a{2}|%(?:25)*5[Cc]|%(?:25)*2[Ff]|%(?:25)*3[aA]){1,}){2,}/R";
    reference:url,labs.watchtowr.com/you-wont-hear-about-these-even-in-myths-atlassian-jira-confluence-and-more-pre-auth-arbitrary-file-read-cve-2026-21589/;
    reference:cve,2026-21589;
    classtype:attempted-user;
    sid:2072392; rev:1;
    metadata:affected_product Atlassian, attack_target Server, tls_state TLSDecrypt, created_at 2026_10_08, cve CVE_2026_21589, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, tag Exploit, updated_at 2026_10_08, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
    target:dest_ip;
)

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