CVE-2026-82455Public exploitHinoki check available

Arbitrary file write via symlinked extraction path

Published Aug 29, 2026 · Updated Aug 29, 2026

Path traversal in RubyGems 3.2.30 through 4.0.12 allows local users to write files outside a gem extraction directory. Gem::Package#extract_tar_gz validates lexical paths but does not resolve an existing parent directory before File.open follows its symlink. Exploitation requires a pre-existing symlink in a reused or shared destination and another user or process to extract a gem into it.

CVSS severity6.9
Medium
EPSS probabilityUnavailable
No score available in this record
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Path traversal in RubyGems 3.2.30 through 4.0.12 allows local users to write files outside a gem extraction directory. Gem::Package#extract_tar_gz validates lexical paths but does not resolve an existing parent directory before File.open follows its symlink. Exploitation requires a pre-existing symlink in a reused or shared destination and another user or process to extract a gem into it.

The record

CVE
CVE-2026-82455
Published
Aug 29, 2026
Updated
Aug 29, 2026
Vendor
libwww-perl
Product
RubyGems
Classifications
CWE-59
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 29, 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=3.2.30 <4.0.13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

libwww-perl · RubyGemsversion=3.2.30 <4.0.13

Published CVSS scores

7.1VulnCheck CNACVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
6.9VulnCheck CNACVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

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-59Improper Link Resolution Before File Access ('Link Following')

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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