Evidence-led vulnerability intelligence · 2026-10-21 21:47 IST

CVE-2026-113789

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.0, an attacker can craft a PDF that causes large memory usage or long runtimes when an application retrieves the document's form fields. This issue is fixed in version 6.21.0.

MEDIUM · 6.0

Executive briefing

The source record describes: pypdf is a free and open-source pure-python PDF library. Prior to 6.21.0, an attacker can craft a PDF that causes large memory usage or long runtimes when an application retrieves the document's form fields. This issue is fixed in version 6.21.0. The practical risk depends on whether an affected product/version is present, reachable and configured in an exploitable way. Review the affected-product evidence and linked vendor advisories before assigning exposure status.

Assessment: Potential exposure only — validate the installed product, exact version, configuration and vendor applicability before treating an asset as confirmed vulnerable.

Evidence confidence: Moderate Evidence-derived, not an exploitability verdict

Severity & attack characteristics

6.0 / 10 · 4.0

CVSS vector:
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack vectorN

Attack complexityL

Attack requirementsP

Privileges requiredN

User interactionP

ScopeX

Technical explanation & impact

The technical mechanism is not expanded beyond the source description unless a referenced advisory supplies additional evidence. Read the linked vendor/CERT advisories for root-cause detail.

Potential impact must be interpreted from the published CVSS impact metrics and the affected component. A CVSS impact score is not proof that a particular asset is exploitable.

Weakness classification

CWE-400CWE-407

Affected products and versions

Products below are parsed from NVD vulnerable CPE configuration entries. Version boundaries are shown as published; verify applicability with the vendor.

Vendor	Product	Version evidence
py-pdf	pypdf	before 6.21.0

Remediation & validation

Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
Validate the remediation with a version check and vulnerability rescan, then retain change evidence.

No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.

Vendor advisories, patches & exploit references

https://github.com/py-pdf/pypdf/commit/5ef728f0e16d225c853e89f861ba0a67402fe3f2 PATCH security-advisories@github.com
https://github.com/py-pdf/pypdf/pull/4219 PATCH security-advisories@github.com
https://github.com/py-pdf/pypdf/releases/tag/6.21.0 VENDOR security-advisories@github.com
https://github.com/py-pdf/pypdf/security/advisories/GHSA-6vvc-x485-93v7 ADVISORY security-advisories@github.com

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