PDFio < 1.6.5 Dangling Pointer via Dictionary String-Formatting
Summary
| CVE | CVE-2026-77220 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-21 21:17:06 UTC |
| Updated | 2026-08-21 21:17:06 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 7.1 HIGH from [email protected]
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/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
Problem Types: CWE-825 | CWE-825 Expired Pointer Dereference
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 7.1 | HIGH | 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/E:X/C... |
| 4.0 | CNA | CVSS | 7.1 | HIGH | 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 |
| 3.1 | [email protected] | Primary | 6.5 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
| 3.1 | CNA | CVSS | 6.5 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
NonePrivileges Required
LowUser Interaction
NoneConfidentiality
NoneIntegrity
HighAvailability
NoneSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/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
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
HighAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Michaelrsweet | Pdfio | affected 1.6.5 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/michaelrsweet/pdfio/releases/tag/v1.6.5 | [email protected] | github.com | |
| github.com/michaelrsweet/pdfio/commit/22b9afc800c5833f9e851e35938972bd4c... | [email protected] | github.com | |
| www.vulncheck.com/advisories/pdfio-dangling-pointer-via-dictionary-string-forma... | [email protected] | www.vulncheck.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Joshua Rogers (AISLE Research) (en)
There are currently no legacy QID mappings associated with this CVE.