PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting function that stores a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, attackers or concurrent users can trigger stack memory reuse across requests, causing cross-tenant document content corruption by silently overwriting one caller's dictionary string values with another caller's data.

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
michaelrsweet pdfio affected
Version Status Constraints
0 affected < 1.6.5

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Project Subscriptions

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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/michaelrsweet/pdfio/commit/22b9afc800c5833f9e851e35938972bd4c76a357 cve-icon cve-icon
https://github.com/michaelrsweet/pdfio/releases/tag/v1.6.5 cve-icon cve-icon
https://www.vulncheck.com/advisories/pdfio-dangling-pointer-via-dictionary-string-formatting cve-icon cve-icon
History

Fri, 21 Aug 2026 21:15:00 +0000

Type Values Removed Values Added
Description PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting function that stores a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, attackers or concurrent users can trigger stack memory reuse across requests, causing cross-tenant document content corruption by silently overwriting one caller's dictionary string values with another caller's data.
Title PDFio < 1.6.5 Dangling Pointer via Dictionary String-Formatting
Weaknesses CWE-825
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'}

cvssV4_0

{'score': 7.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-21T20:54:34.762Z

Reserved: 2026-08-20T18:25:46.943Z

Link: CVE-2026-77220

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-21T21:17:06.737

Modified: 2026-08-21T21:17:06.737

Link: CVE-2026-77220

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-21T22:45:04Z

Weaknesses