MEDIUM 6.5

GHSA-xg43-5579-qw6v

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

Details

### 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 bomb** — `getFromName()` 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`](https://github.com/adawolfa/isdoc/commit/935fb2aa41ceddfcf43174a61a36ec620611a105) (backported, released as 1.4.3 / 1.5.1 / 1.6.1) and [`02a1012`](https://github.com/adawolfa/isdoc/commit/02a10123a3d5fd92950b8e4952959317c0a18952) (master, released as 2.0.0). - CWE-409 (Improper Handling of Highly Compressed Data), CWE-400 (Uncontrolled Resource Consumption).