Bug 2543853 (CVE-2026-94029) - CVE-2026-94029 org.apache.sshd/sshd-sftp: Apache MINA SSHD: Denial of Service via memory exhaustion in SFTP check-file extension
Summary: CVE-2026-94029 org.apache.sshd/sshd-sftp: Apache MINA SSHD: Denial of Service...
Keywords:
Status: NEW
Alias: CVE-2026-94029
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-30 09:47 UTC by OSIDB Bzimport
Modified: 2026-09-30 16:05 UTC (History)
19 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-09-30 09:47:14 UTC 
Server-side memory exhaustion in Apache MINA SSHD 1.0.0 to 2.19.0 and 3.0.0-M1 to 3.0.0-M5, component sshd-sftp, in the SFTP v6 check-file-name/check-file-handle extension. Apache MINA SSHD is a Java library for client-side and server-side SSH.




Using a very small "block size" (for instance 256, which is the minimum) on a huge file generates many (file size / block size) hashes. The resulting SFTP reply message was accumulated fully in memory server-side, which could, with a suitably large (possibly sparse) file exhaust the server-side memory, taking down the server.




Users are recommended to upgrade to version 2.20.0 or 3.0.0-M6, which fix this issue by imposing a maximum limit on the size of the reply. Many SFTP implementations have a general limit on the size of SFTP messages anyway; typically 256kB as in OpenSSH or also in Apache MINA SSHD.
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