- Published
- Source
- Security Affairs
- Filed under
- Zero-days, Malware & exploits
- Vulnerabilities
- 1 CVE Exploited
U.S. Cybersecurity and Infrastructure Security Agency (CISA) adds Atlassian flaw to its Known Exploited Vulnerabilities catalog. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added an Atlassian flaw, tracked as CVE-2026-21589 (CVSS score of 9.3), to its Known Exploited Vulnerabilities (KEV) catalog. In early October, threat actors started exploiting CVE-2026-21589, a critical arbitrary file access flaw…
If you run the affected product
- Find every instance – especially the ones reachable from the internet.
- Apply the vendor's patch or mitigation now: exploited flaws are fixed in days, not at the next patch cycle.
- Then check for signs it was used before you patched: web shells, new accounts, unusual outbound traffic.
More helpCISA's Known Exploited Vulnerabilities catalogue (opens in a new tab)
The vulnerabilities in this story
CVE-2026-21589 in the NVD (opens in a new tab)
- CVSS9.3Critical
- EPSS13%chance of exploitation in 30 days
- CISA KEVExploitedon the list since 15 Oct
Exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog (CC0). Exploit prediction: EPSS by FIRST. This product uses the NVD API but is not endorsed or certified by the NVD.
MyCyberWay training
Blue Team Analyst · Vulnerability Management
You can't patch everything at once. Learn what to fix first.
In our Blue Team Analyst programme you run a vulnerability scan, prioritise the output with CVSS, EPSS and asset criticality, and track remediation to closure with the teams who own the fix.
- Read scanner output properly
- Prioritise with CVSS, EPSS and asset criticality
- Track remediation to closure
Headlines and short summaries only, except where a public body publishes under an open licence. Every story links to its publisher, who owns it. MyCyberWay does not edit or endorse third-party reporting.
