CVE-2026-77220: Expired Pointer Dereference in michaelrsweet pdfio
PDFio versions prior to 1.6.5 contain a dangling pointer vulnerability in the dictionary string-formatting function. This flaw involves storing a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, this can lead to stack memory reuse across requests, causing silent corruption of document content by overwriting one caller's dictionary string values with another's data.
AI Analysis
Technical Summary
CVE-2026-77220 is a dangling pointer vulnerability in michaelrsweet's PDFio library before version 1.6.5. The issue arises because the dictionary string-formatting function stores a pointer to a stack-local buffer rather than copying the string, leading to use-after-scope conditions. In environments with concurrent or pooled requests, this can cause cross-tenant document content corruption due to stack memory reuse, where one caller's dictionary string values are overwritten by another's data.
Potential Impact
The vulnerability can cause silent corruption of document content in multi-threaded or pooled-request environments by overwriting dictionary string values across different callers. This may lead to data integrity issues in applications using the affected PDFio versions. There is no indication of direct code execution or privilege escalation, but the impact on data correctness is significant.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or patch link is provided, users should monitor vendor communications for updates. Until a fix is available, avoid running PDFio in multi-threaded or pooled-request environments where this vulnerability could be triggered.
CVE-2026-77220: Expired Pointer Dereference in michaelrsweet pdfio
Description
PDFio versions prior to 1.6.5 contain a dangling pointer vulnerability in the dictionary string-formatting function. This flaw involves storing a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, this can lead to stack memory reuse across requests, causing silent corruption of document content by overwriting one caller's dictionary string values with another's data.
CVSS v4.0
Score 7.1high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-77220 is a dangling pointer vulnerability in michaelrsweet's PDFio library before version 1.6.5. The issue arises because the dictionary string-formatting function stores a pointer to a stack-local buffer rather than copying the string, leading to use-after-scope conditions. In environments with concurrent or pooled requests, this can cause cross-tenant document content corruption due to stack memory reuse, where one caller's dictionary string values are overwritten by another's data.
Potential Impact
The vulnerability can cause silent corruption of document content in multi-threaded or pooled-request environments by overwriting dictionary string values across different callers. This may lead to data integrity issues in applications using the affected PDFio versions. There is no indication of direct code execution or privilege escalation, but the impact on data correctness is significant.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or patch link is provided, users should monitor vendor communications for updates. Until a fix is available, avoid running PDFio in multi-threaded or pooled-request environments where this vulnerability could be triggered.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-20T18:25:46.943Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a88be1bacd9273b49bcc6c5
Added to database: 08/21/2026, 21:07:39 UTC
Last enriched: 08/21/2026, 21:22:42 UTC
Last updated: 08/21/2026, 21:32:09 UTC
Views: 4
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