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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2021-36978

20
FAUCET Score

CVE-2021-36978 is a heap-based buffer overflow vulnerability affecting QPDF versions 9.x through 9.1.1 and 10.x through 10.0.4. This flaw, rated Medium severity (CVSS 5.5), can lead to a denial of service if a downstream write operation fails during ASCII85 decoding. While it requires user interaction and local access, there is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
>= 9.0.0, <= 9.1.1CPE matchmatch criteria
cpe:2.3:a:qpdf_project:qpdf:*:*:*:*:*:*:*:*
>= 10.0.0, <= 10.0.4CPE matchmatch criteria
cpe:2.3:a:qpdf_project:qpdf:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.5MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.27%
Probability of exploitation in next 30 days
EPSS Percentile
66.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0127 is in the 77th percentile among its peer group of 5,765 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: qpdf

Vendor Advisories (1)

redhatCVE-2021-36978Moderate

qpdf: heap-based buffer overflow in Pl_ASCII85Decoder::write() when a certain downstream write fails

Jan 4, 2021

References

bugs.chromium.org / p/oss-fuzz/issues/detail
PatchThird Party Advisory
github.com / google/oss-fuzz-vulns/blob/main/vulns/qpdf/OSV-2020-2245.yaml
Third Party Advisory
github.com / qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5
PatchThird Party Advisory
github.com / qpdf/qpdf/issues/492
lists.debian.org / debian-lts-announce/2023/08/msg00037.html
security.gentoo.org / glsa/202401-20