CVE-2026-103000

pypdf: Possible large memory usage when retrieving alphabetical page labels

HIGH
7.5
CVSS Score
Published: September 30, 2026 at 08:13 PM UTC
Updated: October 5, 2026 at 03:03 PM UTC
2 products affected across 2 vendorsPypdfPypdf

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.19.0, a crafted PDF can provide unusually large alphabetical page-label values that cause pypdf/_page_labels.py to generate strings beyond a reasonable page-label length when an application retrieves document page labels, consuming excessive memory and potentially making the application unavailable. This issue is fixed in version 6.19.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 6.19.0
Affected range stops below 6.19.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

x_refsource_CONFIRMVendor Advisory
Source: cverecord
https://github.com/py-pdf/pypdf/security/advisories/GHSA-w23x-9jrw-r45c
x_refsource_MISCPatchIssue Tracking
Source: cverecord
https://github.com/py-pdf/pypdf/pull/4096
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/py-pdf/pypdf/releases/tag/6.19.0

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-400

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