EUVD-2026-29863Published

Snappier: Infinite loop in SnappyStream decompression on malformed framed input

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

CVE-2026-44302

No KEV entry is attached to this observation; this is not evidence that exploitation is absent.

FIRST EPSS: 0.32 % · percentile 24.38 % · scored 27 Oct 2026.

Observed 27 Oct 2026 15:46:19 UTC · Complete immutable risk JSON

cve-program · CVE-2026-44302

Published

Snappier is a high performance C# implementation of the Snappy compression algorithm. Prior to 1.3.1, Snappier.SnappyStream enters an uncatchable infinite loop when decompressing a malformed framed-format Snappy stream as small as 15 bytes. This vulnerability is fixed in 1.3.1.

Source published: 12 May 2026 21:33:07 UTC
Source modified: 18 May 2026 15:10:25 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

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CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

euvd · EUVD-2026-29863

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: May 12, 2026, 9:33:07 PM

dateUpdated: May 18, 2026, 3:10:25 PM

Source published: May 12, 2026, 9:33:07 PM (timezone not stated)
Source modified: May 18, 2026, 3:10:25 PM (timezone not stated)
Observed here: 28 Oct 2026 06:06:55 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd · CVE-2026-44302

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Deferred

Weakness classifications: CWE-835

Original publisher date fields

published: 2026-05-12T22:16:36.997

lastModified: 2026-10-26T14:10:00.130

Source published: 12 May 2026 22:16:36 UTC
Source modified: 26 Oct 2026 14:10:00 UTC
Observed here: 27 Oct 2026 11:12:09 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

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CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

osv · GHSA-pggp-6c3x-2xmx

Published

### 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 ```csharp 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).

Source published: 6 May 2026 20:53:23 UTC
Source modified: 13 May 2026 16:57:26 UTC
Observed here: 23 Oct 2026 16:01:25 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Publisher rating · HIGH