CVE-2026-49460

Processing delays via inefficient PNG predictor decoding

Published Jun 22, 2026 · Updated Jun 22, 2026

Algorithmic complexity in pypdf before 6.12.2 allows attackers to cause long runtimes by processing a crafted PDF stream. The FlateDecode._decode_png_prediction routine repeatedly rebuilds immutable byte sequences while applying PNG predictor filters to attacker-controlled row data. Exposure requires a consuming application to decode the crafted stream; the resulting CPU cost can delay or interrupt that application's PDF-processing work.

CVSS severity5.1
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

Algorithmic complexity in pypdf before 6.12.2 allows attackers to cause long runtimes by processing a crafted PDF stream. The FlateDecode._decode_png_prediction routine repeatedly rebuilds immutable byte sequences while applying PNG predictor filters to attacker-controlled row data. Exposure requires a consuming application to decode the crafted stream; the resulting CPU cost can delay or interrupt that application's PDF-processing work.

The record

CVE
CVE-2026-49460
Published
Jun 22, 2026
Updated
Jun 22, 2026
Vendor
py-pdf
Product
pypdf
Classifications
CWE-407, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 22, 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=< 6.12.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

py-pdf · pypdfversion=< 6.12.2

Published CVSS scores

4.0GitLab Advisory DatabaseCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
5.1GitHubCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
3.3NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-407Inefficient Algorithmic Complexity
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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