Arbitrary file upload in Krajowa Izba Rozliczeniowa Szafirhost

CVE-2026-13165

SzafirHost verifies the downloaded native library archive with one JarFile parser (reading the Central Directory) but extracts native libraries with JarInputStream parser (reading sequentially from local file headers). An attacker who controls the served archive can insert a malicious DLL/SO/DYLIB as a local-file-header entry between the last legitimate entry and the Central Directory, without adding it to the Central Directory. The signature verifier never sees the injected entry and accepts the archive as validly signed; the extractor reads it sequentially and writes the attacker library to the native temp directory with no hash check), while the archive-size check still passes. This can lead to remote code execution. This issue was fixed in version 1.2.2.

Vulnerability class: Unrestricted File Upload

Published · last modified .

EPSS exploit prediction

EPSS: 0.007 (51.6th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 51.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-13165: held from 0.007 to 0.007.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Weakness classification (CWE)

References