Path Traversal in SharpCompress (CVE-2026-44788)
Summary
Path traversal in SharpCompress (CVE-2026-44788). Data can be tampered with by attackers. Exploitable via WriteToDirectoryInternal. Mitigation: upgrade to 0.48.0 or later.
Original description
The description as published by the source.
Summary
A path traversal vulnerability in IArchive.WriteToDirectory() allows a malicious archive to create directories outside the intended extraction root. For TAR archives, this can be escalated to arbitrary file writes by chaining with a symlink entry, giving a full write primitive on the target filesystem subject to the permissions of the running process.
Details
The vulnerable code is in the directory-entry branch of WriteToDirectoryInternal (sync, IArchiveExtensions.cs:48–61) and WriteToDirectoryAsyncInternal (async, IAsyncArchiveExtensions.cs:70–84):
var dirPath = Path.Combine(destinationDirectory, entry.Key);
Directory.CreateDirectory(Path.GetDirectoryName(dirPath + "/"));
No Path.GetFullPath() normalisation and no bounds check are applied before the Directory.CreateDirectory call. Two .NET Path.Combine behaviours make this exploitable:
- Relative traversal:
Path.Combine("/safe/extract", "../../evil")→ the OS resolves..segments on the raw path, placing the directory outside the extraction root. - Absolute path override:
Path.Combine("/safe/extract", "/tmp/evil")→ returns"/tmp/evil"— the base is discarded entirely for rooted paths.
File entries are not directly affected — they route through ExtractionMethods.WriteEntryToDirectory which applies the correct guard (GetFullPath + StartsWith, see ExtractionMethods.cs:54–65). The directory-entry branch is a separate fast-path that was added withou…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-44788 has been found in SharpCompress.
Attackers can target a specific entry point like WriteToDirectoryInternal over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 5.9/10.
What to do: upgrade SharpCompress to 0.48.0 or later.
If unsure, ask your IT team or search "SharpCompress CVE-2026-44788" on the vendor's site.
CVE-2026-44788 (SharpCompress) — CWE-22 / CVSS v3 5.9
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: WriteToDirectoryInternal / WriteToDirectoryAsyncInternal / Directory.CreateDirectory / Path.Combine
Patched: 0.48.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Path traversal (CWE-22) exists in SharpCompress. Attackers reach the vulnerable code path via WriteToDirectoryInternal without authentication.
Check the vendor advisory for the affected versions of SharpCompress. Attack surface: WriteToDirectoryInternal / WriteToDirectoryAsyncInternal / Directory.CreateDirectory / Path.Combine.
Severity: Medium (CVSS 5.9/10). Data can be tampered with by attackers.
Update to 0.48.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'SharpCompress' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'SharpCompress' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
SharpCompressを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade SharpCompress to 0.48.0ステージング環境で 0.48.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com