Wednesday’s brief: Atlassian Data Center, then Struts, Smarty’s cache, Osaka’s outage

By George Bailey   Published: 10/07/26   Updated: 10/10/26   3 min read

Published: 10/07/26

Wednesday’s clock starts on the tools your developers live in. Atlassian disclosed a critical unauthenticated file-read across eight Data Center products on Sunday, and self-hosted Confluence, Jira and Bitbucket still need the fixed builds. Also on the desk: a Struts OGNL path that only bites the legacy REST mapper, a Smarty cache-marker bug under a lot of PHP apps, and Osaka Metropolitan University’s ransomware outage that cancelled classes into Thursday. Reminder from Monday’s brief: the NetScaler SAML KEV due date is today, Wednesday October 7 — confirm Sunday’s builds are actually installed.

Lead Story

Your Confluence and Jira boxes can leak known files without a login — patch Data Center today

CVE-2026-21589 lets an unauthenticated attacker read specific files from the web application root on Bitbucket, Confluence, Jira Software, Jira Service Management, Bamboo, Crowd, Crucible and Fisheye Data Center. Atlassian scored it 9.3. Cloud is patched. Take internet-facing instances offline or apply the temporary WAF rule until you hit the fixed builds.

Why it matters: Source, wiki, tickets and identity on one unauthenticated read path. “They need to know the filename” is not a control.

See the patch list →

Also Worth Your Attention

If your Java app still uses Struts’ old REST mapper, upgrade before someone tests it

S2-075 / CVE-2026-104711 is OGNL injection that can reach remote code execution when the legacy RESTful action mapper is configured. Default and restful2 mappers are fine. Move to Struts 6.12.0 or 7.4.0.

Why it matters: The risky mapper lives in apps nobody has opened since 2018.

Check the mapper →

The PHP template engine under your storefront needs a quiet update

Smarty CVE-2026-82531 lets forged cache markers inject PHP when caching and unescaped output line up. Fixed in 4.5.8 / 5.8.5. Clear the template cache after you update, and ask vendors who embed Smarty for their bump.

Why it matters: Millions of installs, most of them transitive.

Update the lockfile →

Osaka’s university lost hundreds of servers to ransomware — classes stay cancelled through Thursday

OMU reports a suspected ransomware hit that took down roughly 500 servers and may touch data for about 130,000 people. Theft not confirmed. In-person classes planned to resume Friday. Hospital EMR stayed up.

Why it matters: When virtualization and backups share a fate, “we have backups” is a wish.

Run the restore drill →

Wednesday brief — patch Atlassian Data Center for CVE-2026-21589 (unauth file read, 8 products; cloud already fixed). Struts S2-075: upgrade to 6.12.0/7.4.0 if legacy REST mapper is on. Smarty to 4.5.8/5.8.5 then clear caches. OMU ransomware: ~500 servers, classes through Thu — prove offline restores. Reminder: NetScaler SAML KEV due TODAY (Wed Oct 7).

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George Bailey

George Bailey is the byline of the CyberExperts editorial desk, the team behind the CyberExperts Daily Brief. The desk covers vulnerabilities, breaches and security news from vendor advisories, CISA alerts and other primary sources, and links those sources in every story. Questions or corrections: [email protected].