CVE-2026-44722

Plaintext recovery via incorrect AE-1 selection

Published Jul 17, 2026 · Updated Jul 17, 2026

Information disclosure in pyzipper before 0.4.0 allows attackers with an encrypted archive to recover low-entropy plaintext via exposed CRC32 values. The precedence expression in pyzipper/zipfile_aes.py evaluates the size and compression test incorrectly, so AE-2 is never selected automatically and AE-1 writes plaintext CRC32 values into headers and unseekable-archive data descriptors. Possession of the archive is required; comparing candidate CRC32 values exposes only small or low-entropy content in practical attacks, while AES encryption remains intact.

CVSS severity6.2
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in pyzipper before 0.4.0 allows attackers with an encrypted archive to recover low-entropy plaintext via exposed CRC32 values. The precedence expression in pyzipper/zipfile_aes.py evaluates the size and compression test incorrectly, so AE-2 is never selected automatically and AE-1 writes plaintext CRC32 values into headers and unseekable-archive data descriptors. Possession of the archive is required; comparing candidate CRC32 values exposes only small or low-entropy content in practical attacks, while AES encryption remains intact.

The record

CVE
CVE-2026-44722
Published
Jul 17, 2026
Updated
Jul 17, 2026
Vendor
Daniel Hillier
Product
pyzipper
Classifications
CWE-480
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 17, 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=< 0.4.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Daniel Hillier · pyzipperversion=< 0.4.0

Published CVSS scores

6.2GitHubCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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-480Use of Incorrect Operator

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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