#VU66595 Heap-based buffer overflow in QPDF - CVE-2021-36978

Vulnerability identifier: #VU66595

Vulnerability risk: High

CVSSv4.0: 7.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-36978

CWE-ID: CWE-122

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
QPDF
Client/Desktop applications / File managers, FTP clients

Vendor: SourceForge

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error within the Pl_ASCII85Decoder::write() function when processing PDF files. A remote attacker can pass specially crafted file to the application, trigger a heap-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

QPDF: 9.0.0 - 10.4.0

---

External links
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28262
https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/qpdf/OSV-2020-2245.yaml

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.