CVE-2024-27280Network attack vector

Process-memory disclosure via incorrect StringIO expansion

Published May 8, 2024 · Updated Nov 4, 2025

Buffer over-read in StringIO bundled with Ruby 3.0.x through 3.0.6 and 3.1.x through 3.1.4 allows attackers to disclose process memory. The strio_unget_bytes function miscalculates the expansion passed to rb_str_modify_expand when pushed-back data exceeds the current position, extending the string beyond initialized content. A caller must supply oversized data to ungetbyte or ungetc and then read the exposed bytes with gets; disclosure is limited to memory available within the Ruby process.

CVSS severity9.8
Critical
EPSS probability2.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer over-read in StringIO bundled with Ruby 3.0.x through 3.0.6 and 3.1.x through 3.1.4 allows attackers to disclose process memory. The strio_unget_bytes function miscalculates the expansion passed to rb_str_modify_expand when pushed-back data exceeds the current position, extending the string beyond initialized content. A caller must supply oversized data to ungetbyte or ungetc and then read the exposed bytes with gets; disclosure is limited to memory available within the Ruby process.

The record

CVE
CVE-2024-27280
Published
May 8, 2024
Updated
Nov 4, 2025
Vendor
libwww-perl
Product
Ruby
Classifications
CWE-126, CWE-120
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 8, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 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?

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

  1. Affected versionversion=3.0.3 <=3.0.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

libwww-perl · Rubyversion=3.0.3 <=3.0.6

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.3GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-126Buffer Over-read
CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

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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