CVE-2026-71870

pypdf: Possible large memory usage for large /ToUnicode streams

LOW
3.3
CVSS Score
Published: August 7, 2026 at 07:28 PM UTC
Updated: October 24, 2026 at 03:10 PM UTC
2 products affected across 2 vendorsPypdfPypdf

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Severity
LOW3.3
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, a crafted PDF can cause large memory consumption when pypdf/_cmap.py function parse_bfrange parses unusually large source-code or destination-string tokens in a font /ToUnicode CMap during text extraction. This issue is fixed in 6.15.0.

Affected

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

v < 6.15.0
Affected range stops below 6.15.0, 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-fp3f-mc75-235c
x_refsource_MISCPatch
Source: cverecord
https://github.com/py-pdf/pypdf/pull/3944
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/py-pdf/pypdf/releases/tag/6.15.0

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-400

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