Bug 2564352 (CVE-2026-63201)

Summary: CVE-2026-63201 netopeer2: Netopeer2: Denial of Service via format string in get RPC filter
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Netopeer2. This vulnerability allows an authenticated remote user to cause a Denial of Service (DoS) by sending a crafted get Remote Procedure Call (RPC) message containing format specifiers in an invalid filter. When processing the request, the server passes the unvalidated input directly to its internal logging mechanism, causing the application to crash.
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Bug Depends On: 2565447, 2565448, 2565449    
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Description OSIDB Bzimport 2026-10-30 22:34:52 UTC 
Netopeer2 is a server for implementing network configuration management based on the `NETCONF` Protocol. In affected versions, a low-privileged authenticated `NETCONF` user can remotely crash `netopeer2-server` by sending a `get RPC` with an invalid `subtree filter` whose text contains format specifiers. In `src/netconf.c`, `np2srv_rpc_get_cb()` sends the invalid value through `ERR()` to `np2log_printf()`, where `vsnprintf()` first formats the message safely. In `src/log.c`, that already formatted buffer is subsequently passed to `np2log()` as the format string itself, causing `vsyslog()` to interpret attacker-controlled percent sequences and read invalid pointer arguments. The reported denial of service was confirmed on version 2.8.7 using `NETCONF`-over-SSH and AddressSanitizer; reliable remote code execution was not confirmed. `The advisory identifies 2.8.8 as patched`; repository comparisons verify the fix in public release 2.8.21. The affected/fixed boundary remains unresolved because no public 2.8.8 tag was located, which does not establish the status of an untagged 2.8.8 build.