CVE-2021-33294Public exploit

Process hang via cyclic symbol-version offsets

Published Jul 18, 2023 · Updated Oct 28, 2024

Infinite loop in elfutils 0.183 allows context-dependent attackers to indefinitely hang eu-readelf through a crafted ELF file. The handle_symtab function advances through attacker-controlled vna_next, vn_next, and vd_next offsets without checking for wraparound, allowing cyclic traversal. Exploitation requires the crafted file to be opened with eu-readelf; the affected process consumes resources without terminating, while upstream disputes that this local tool defect has security impact.

CVSS severity5.5
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Infinite loop in elfutils 0.183 allows context-dependent attackers to indefinitely hang eu-readelf through a crafted ELF file. The handle_symtab function advances through attacker-controlled vna_next, vn_next, and vd_next offsets without checking for wraparound, allowing cyclic traversal. Exploitation requires the crafted file to be opened with eu-readelf; the affected process consumes resources without terminating, while upstream disputes that this local tool defect has security impact.

The record

CVE
CVE-2021-33294
Published
Jul 18, 2023
Updated
Oct 28, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-835, T1204.002
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Jul 18, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.5SUSECVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
5.5IBMCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

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

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1204.002Malicious File

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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