Summary
Snappier.SnappyStream enters an uncatchable infinite loop when decompressing a malformed framed-format Snappy stream as small as 15 bytes.
Details
The hang manifests as a userspace busy loop with SnappyStreamDecompressor.Decompress repeatedly calling Crc32CAlgorithm.Append. The exact non-terminating loop in or above Decompress has not been traced further.
PoC
using System.IO.Compression;
using Snappier;
byte[] data = { 0x00, 0x04, 0x00, 0x00, 0x64, 0x4e, 0x6c, 0x71, 0x79, 0x20, 0x77, 0x6f, 0x72, 0x6c, 0x64 };
using var src = new MemoryStream(data);
using var snap = new SnappyStream(src, CompressionMode.Decompress);
using var dst = new MemoryStream();
snap.CopyTo(dst); // never returns
Impact
A caller using SnappyStream on attacker-controlled bytes can be made to spin forever and burn a thread until the process is killed. try/catch around the stream operation can't recover (no exception is thrown).
CVE-2026-44302 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.3.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-44302? CVE-2026-44302 is a high-severity security vulnerability in Snappier (nuget), affecting versions <= 1.3.0. It is fixed in 1.3.1.
- How severe is CVE-2026-44302? CVE-2026-44302 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of Snappier are affected by CVE-2026-44302? Snappier (nuget) versions <= 1.3.0 is affected.
- Is there a fix for CVE-2026-44302? Yes. CVE-2026-44302 is fixed in 1.3.1. Upgrade to this version or later.
- Is CVE-2026-44302 exploitable, and should I be worried? Whether CVE-2026-44302 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
- What actually determines whether CVE-2026-44302 is exploitable, and how bad it is? 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.
- How do I fix CVE-2026-44302? Upgrade
Snappierto 1.3.1 or later.