Vulnerability Database

362,176

Total vulnerabilities in the database

adawolfa/isdoc: Uncontrolled resource consumption (decompression bomb) when reading untrusted ISDOCX or PDF files — adawolfa / isdoc

Uncontrolled Resource Consumption

Impact

adawolfa/isdoc reads ISDOC invoices from ISDOCX (ZIP) archives and from PDF files with embedded ISDOC documents and supplements. Affected versions inflate ZIP entries and read embedded files without validating their uncompressed size, so a small crafted file can amplify into gigabytes:

  • ISDOCX decompression bombgetFromName() inflates the ISDOC document and binary supplements with no size cap.
  • saveTo() disk-fill — the supplement copy loop writes inflated bytes to disk with no running byte budget, so a bomb can exhaust disk even if the central-directory size is under-reported.
  • PDF embedded files — an embedded file whose declared Length is enormous is read and digested with no upper bound.

Exploitation requires the application to parse an attacker-supplied .isdocx or .pdf (the typical use is generating files or parsing files from trusted vendors, so a user must be induced to process a malicious file). When that happens the process can be driven to exhaust memory or disk, causing denial of service. There is no confidentiality or integrity impact — availability only.

Patches

Fixed in 1.4.3, 1.5.1, 1.6.1 and 2.0.0. The readers now:

  • read the uncompressed size from the ZIP central directory (statName()) and reject entries over a cap before inflating — 256 KB (DocumentSizeLimit) for the ISDOC document, 32 MB (SizeLimit) for supplements;
  • enforce a running byte budget in saveTo() and unlink the partial file on overflow;
  • reject PDF-embedded files whose declared Length exceeds 256 MB before reading or digesting them.

New exceptions ReaderException::zipEntryTooLarge(), SupplementException::supplementTooLarge() and ReaderException::pdfSupplementTooLarge() surface the rejection.

Unsupported versions

Versions before 1.4.0 (the 1.0–1.3 lines) are also affected and will not receive a fix, because they target end-of-life PHP. Users on those lines should upgrade to a maintained release — 1.4.3, 1.5.1, 1.6.1, or 2.0.0.

Workarounds

No code-level workaround exists in affected versions; upgrading is the fix. As mitigation, restrict parsing to trusted input, or enforce an external size / decompression limit (validate ZIP entry sizes, cap process memory) before handing files to the library.

Resources

  • Decompression-bomb fix: commit 935fb2a (backported, released as 1.4.3 / 1.5.1 / 1.6.1) and 02a1012 (master, released as 2.0.0).
  • CWE-409 (Improper Handling of Highly Compressed Data), CWE-400 (Uncontrolled Resource Consumption).
  • Published: Jul 15, 2026
  • Updated: Jul 16, 2026
  • GHSA: GHSA-xg43-5579-qw6v
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 6.5
  • AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.