CVE-2026-57204

pypdf: Missing stream length values ignore defined limits

MEDIUM
6.5
CVSS Score
Published: June 30, 2026 at 09:59 PM UTC
Updated: October 25, 2026 at 09:10 PM UTC
2 products affected across 2 vendorsPypdfPypdf

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value. This issue has been fixed in version 6.13.3.

Affected

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

v < 6.13.3
Affected range stops below 6.13.3, so it looks safe — our inference, not a vendor statement
v < 6.13.3
Affected range stops below 6.13.3, 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 (2)

x_refsource_CONFIRMPatchVendor Advisory
Source: cverecord
https://github.com/py-pdf/pypdf/security/advisories/GHSA-jm82-fx9c-mx94
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/py-pdf/pypdf/releases/tag/6.13.3

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
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-400

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