CVE-2026-31826Public exploit

Memory exhaustion via unchecked stream length

Published Mar 10, 2026 · Updated Mar 10, 2026

Resource exhaustion in py-pdf pypdf before 6.8.0 allows attackers to consume memory by supplying a crafted PDF content stream. DictionaryObject.read_from_stream trusts the stream's declared /Length and passes it to stream.read without enforcing a maximum, allocating memory for data absent from the file. The PDF must be parsed from a buffer of unknown size, such as an open binary file object; file paths and BytesIO buffers are not reported to trigger the issue.

CVSS severity6.8
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in py-pdf pypdf before 6.8.0 allows attackers to consume memory by supplying a crafted PDF content stream. DictionaryObject.read_from_stream trusts the stream's declared /Length and passes it to stream.read without enforcing a maximum, allocating memory for data absent from the file. The PDF must be parsed from a buffer of unknown size, such as an open binary file object; file paths and BytesIO buffers are not reported to trigger the issue.

The record

CVE
CVE-2026-31826
Published
Mar 10, 2026
Updated
Mar 10, 2026
Vendor
py-pdf
Product
pypdf
Classifications
CWE-770, T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 6.8.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

py-pdf · pypdfversion=< 6.8.0

Published CVSS scores

6.8GitHubCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.5NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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