Kestra OSS: attackers can run commands on it
OFFICIAL NAME: Kestra OSS OS Command Injection Vulnerability
WHAT IT IS · DEVELOPER TOOLSIt holds source code and the keys used to build and ship software.
DO THIS FIRSTPatch it. If it faced the internet, change the keys and passwords stored in it. Not sure if you use it? Send this page to your IT provider or security lead and ask.
TECHNICAL SUMMARY Kestra OSS contains an OS command injection vulnerability that could allow an unauthenticated remote attacker to create and execute arbitrary workflows without credentials.
WHY THIS VERDICT Attacks are confirmed. The vulnerability is 128 days old, so current versions are being attacked. The severity score is critical (10.0).
- HIGHEST CONFIRMED RUNG
- EXPLOITED
- CISA KEV
- LISTED
- EXPLOIT CODE
- PROOF OF CONCEPT CLAIMED
How far has it climbed?
01 TALK
□ NO EVIDENCE YETNEWEST EVIDENCE NONE YETNo evidence yet.
SRC: NONE YET02 EXPOSED
□ NOT TRACKED YETNO SOURCE FOR THIS STEP YETWe have no source that counts exposed systems yet. Internet scan data needs a partnership we do not have. No evidence here does not mean nothing is exposed.
03 TRIED
■ CONFIRMEDNEWEST EVIDENCE · 2 INDEPENDENT SOURCESAttacks that worked are confirmed (step 4), so attempts count as confirmed too.
04 EXPLOITED
■ CONFIRMEDNEWEST EVIDENCE · 2 INDEPENDENT SOURCESKestra OSS contains an OS command injection vulnerability that could allow an unauthenticated remote attacker to create and execute arbitrary workflows without credentials. CISA Vulnrichment marks CVE-2026-49869 as actively exploited.
05 DAMAGE
□ NOT TRACKED YETNO SOURCE FOR THIS STEP YETBreach notices and filings rarely name the flaw that was used, so we cannot link them to this event yet. No evidence here does not mean no harm.
When each thing happened
- DISCLOSED
- EXPLOIT CODE PUBLICCLAIMED
- FIRST ATTACK REPORT
- CISA KEV LISTING
- US FEDERAL DEADLINE
THE FIX
CISA's instruction: apply the vendor's fix, or stop using the product if no fix exists. The deadline CISA set for US federal agencies, Sep 5, 2026, has passed. It is a US government deadline; use it as a guide.
Questions to ask this week
- Do we run Kestra OSS? If yes, is it patched or cut off from the internet?
- Who owns fixing it, and by what date?
- Have we checked for signs of attack since the first report, not just since the patch?
How it unfolded
- Attack activity. JUN 26, 2026CISA Vulnrichment marks CVE-2026-49869 as actively exploited
- JUN 30, 20262 public GitHub repositories claim a proof of concept for CVE-2026-49869
- Attack activity. SEP 1, 2026Kestra OSS OS Command Injection Vulnerability
SOURCES
- [1] CISA Known Exploited Vulnerabilities: Kestra OSS OS Command Injection Vulnerability, SEP 1
- [2] PoC-in-GitHub: 2 public GitHub repositories claim a proof of concept for CVE-2026-49869, JUN 30
- [3] CVE List V5 and CISA Vulnrichment: CISA Vulnrichment marks CVE-2026-49869 as actively exploited, JUN 26