Vulnerability in psd-tools (CVE-2026-27809)
Summary
Vulnerability in psd-tools (CVE-2026-27809). Risk of unauthorized operations or information disclosure. Exploitable via psd_tools.compression. Mitigation: upgrade to 1.12.2 or later.
Original description
The description as published by the source.
Summary
A security review of the psd_tools.compression module (conducted against the fix/invalid-rle-compression branch, commits 7490ffa–2a006f5) identified the following pre-existing issues. The two findings introduced and fixed by those commits (Cython buffer overflow, IndexError on lone repeat header) are excluded from this report.
Findings
1. Unguarded zlib.decompress — ZIP bomb / memory exhaustion (Medium)
Location: src/psd_tools/compression/__init__.py, lines 159 and 162
result = zlib.decompress(data) # Compression.ZIP
decompressed = zlib.decompress(data) # Compression.ZIP_WITH_PREDICTION
zlib.decompress is called without a max_length cap. A crafted PSD file containing a ZIP-compressed channel whose compressed payload expands to gigabytes would exhaust process memory before any limit is enforced. The RLE path is not vulnerable to this because the decoder pre-allocates exactly row_size × height bytes; the ZIP path has no equivalent ceiling.
Impact: Denial-of-service / OOM crash when processing untrusted PSD files.
Suggested mitigation: Pass a reasonable max_length to zlib.decompress, derived from the expected width * height * depth // 8 byte count already computed in decompress().
2. No upper-bound validation on image dimensions before allocation (Low)
Location: src/psd_tools/compression/__init__.py, lines 138 and 193
length = width * height * max(1, d…
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
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-2026-27809 has been found in psd-tools.
Attackers can target a specific entry point like psd_tools.compression over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade psd-tools to 1.12.2 or later.
If unsure, ask your IT team or search "psd-tools CVE-2026-27809" on the vendor's site.
CVE-2026-27809 (psd-tools) — CWE-190
Attack surface: psd_tools.compression / IndexError / zlib.decompress / max_length
Patched: 1.12.2 — 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.
A vulnerability (CWE-190) exists in psd-tools. Attackers reach the vulnerable code path via psd_tools.compression.
Check the vendor advisory for the affected versions of psd-tools. Attack surface: psd_tools.compression / IndexError / zlib.decompress / max_length.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 1.12.2.
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 'psd-tools' . 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
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1Identify exposure identify
grep -r 'psd-tools' . | 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
psd-tools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 psd-tools to 1.12.2ステージング環境で 1.12.2 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
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-27809 psd-tools
- Ubuntu UBUNTU-CVE-2026-27809 psd-tools
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com