Qpdf · Qpdf · CVE-2021-36978
**Name of the Vulnerable Software and Affected Versions**
QPDF versions 9.x through 9.1.1
QPDF versions 10.x through 10.0.4
**Description**
The issue is a heap-based buffer overflow in `Pl ASCII85Decoder::write`, which is called from `Pl AES PDF::flush` and `Pl AES PDF::finish`, occurring when a certain downstream write fails.
**Recommendations**
For QPDF versions 9.x through 9.1.1, update to a version later than 9.1.1 to resolve the issue.
For QPDF versions 10.x through 10.0.4, update to a version later than 10.0.4 to resolve the issue.
As a temporary workaround, consider restricting the use of the `Pl ASCII85Decoder::write` function until a patch is available.