EUVD-2026-38355
GHSA-m2v9-299j-rv96
Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/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
Worst-case assumes network-reachable merge endpoint with no authentication; only availability is impacted via infinite loop with no code execution possible.
Primary rating from Vendor (https://github.com/py-pdf/pypdf).
CVSS VectorVendor: https://github.com/py-pdf/pypdf
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/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
Lifecycle Timeline
3Blast Radius
ecosystem impact- 1 pypi packages depend on pypdf (1 direct, 0 indirect)
Ecosystem-wide dependent count for version 6.13.0.
DescriptionCVE.org
Impact
An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with outlines into a writer.
Patches
This has been fixed in pypdf==6.13.0.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3830.
AnalysisAI
Processing crafted PDF outlines in pypdf versions prior to 6.13.0 triggers an infinite loop during writer merge operations, causing a denial of service. Applications that accept user-supplied PDFs and merge them using PdfWriter are affected - specifically any code path that calls merge() on a PDF whose /Outlines or /Parent hierarchy contains circular references. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the target application runs pypdf version earlier than 6.13.0 AND calls PdfWriter.merge() (or an equivalent merge workflow) on a PDF supplied by the attacker. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | No CVSS score or vector was provided by NVD or the reporting source, and no EPSS data is available, so all severity signals must be inferred. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker uploads a crafted PDF file in which the /Outlines dictionary contains a node whose /Next entry points back to an ancestor, forming a cycle invisible to naive parsers. When a vulnerable pypdf application calls PdfWriter.merge() with this file, _get_filtered_outline() enters an infinite loop, consuming CPU until the worker process hangs or is killed by an OS-level resource limit. … |
| Remediation | Upgrade pypdf to version 6.13.0 or later using pip install 'pypdf>=6.13.0'; the release is confirmed at https://github.com/py-pdf/pypdf/releases/tag/6.13.0. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same technique Denial Of Service
View allVendor StatusVendor
SUSE
Severity: ModerateShare
External POC / Exploit Code
Leaving vuln.today