CVE-2020-36846Network attack vector

Script crash via oversized one-shot decompression input

Published May 30, 2025 · Updated May 30, 2025

Buffer overflow in IO::Compress::Brotli before 0.007 allows remote attackers to crash a consuming script via oversized one-shot input. The bundled decoder's BrotliGetRemainingBytes() helper fails to cap its remaining-byte calculation for chunks larger than 2 GiB, permitting an out-of-bounds copy. Exploitation requires a script to process attacker-controlled data with one-shot decompression; the established consequence is a process crash, not code execution.

CVSS severity9.8
Critical
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in IO::Compress::Brotli before 0.007 allows remote attackers to crash a consuming script via oversized one-shot input. The bundled decoder's BrotliGetRemainingBytes() helper fails to cap its remaining-byte calculation for chunks larger than 2 GiB, permitting an out-of-bounds copy. Exploitation requires a script to process attacker-controlled data with one-shot decompression; the established consequence is a process crash, not code execution.

The record

CVE
CVE-2020-36846
Published
May 30, 2025
Updated
May 30, 2025
Vendor
Timothy Legge
Product
IO::Compress::Brotli
Classifications
CWE-1395, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 30, 2025CVE publishedPublication date reported by the CVE source.
  2. May 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=0 <0.007

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Timothy Legge · IO::Compress::Brotliversion=0 <0.007

Published CVSS scores

9.8UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1395Dependency on Vulnerable Third-Party Component
T1499.004Application or System Exploitation

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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