CVE-2026-55195 is a medium-severity security vulnerability in py7zr (pip), affecting versions <= 1.1.2. It is fixed in 1.1.3.
py7zr's Worker.decompress() extracts archive entries without tracking total decompressed size. A crafted .7z file can exhaust disk or memory before the extraction completes. Measured: 15.6 KB archive → 100 MB output (6,556:1 ratio). Proof of concept: Root cause: Worker.decompress() in py7zr/worker.py writes decompressed data directly to disk without a running total or configurable size limit. There is no equivalent of Python's zipfile max_size parameter. Fix: track cumulative decompressed bytes and raise before writing if a limit is exceeded: Tested on py7zr 0.22.0, Python 3.12, Ubuntu 22.04.
pip
py7zr (<= 1.1.2)py7zr → 1.1.3 (pip)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-55195 is reachable in your applications. Explore open-source security for your team.
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Upgrade py7zr to 1.1.3 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-55195 is a medium-severity security vulnerability in py7zr (pip), affecting versions <= 1.1.2. It is fixed in 1.1.3.
py7zr (pip) versions <= 1.1.2 is affected.
Yes. CVE-2026-55195 is fixed in 1.1.3. Upgrade to this version or later.
Whether CVE-2026-55195 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade py7zr to 1.1.3 or later.