CVE-2026-59937

pypdf: Possible long runtimes for repeated malformed cross-reference entries

HIGH
7.5
CVSS Score
Published: July 8, 2026 at 05:25 PM UTC
Updated: October 25, 2026 at 05:10 PM UTC
2 products affected across 2 vendorsPypdfPypdf

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.14.0, an attacker can craft a PDF with repeated malformed cross-reference streams that cause pypdf to spend long runtimes recovering broken cross-reference table entries. This issue is fixed in version 6.14.0.

Affected

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

v < 6.14.0
Affected range stops below 6.14.0, so it looks safe — our inference, not a vendor statement
v < 6.14.0
Affected range stops below 6.14.0, 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_CONFIRMPatchVendor Advisory
Source: cverecord
https://github.com/py-pdf/pypdf/security/advisories/GHSA-55h5-xmcq-c37v
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/py-pdf/pypdf/pull/3887
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/py-pdf/pypdf/releases/tag/6.14.0

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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