CVE-2026-59874Public exploitNetwork attack vector

Worker hang via negative archive entry size

Published Jul 8, 2026 · Updated Jul 8, 2026

Denial of service in Isaac Z. Schlueter tar before 7.5.18 allows remote attackers to hang workers via a crafted archive. The tar.replace scanner accepts a checksum-valid negative base-256 size and adds it to the 512-byte header step, leaving its position unchanged. Exploitation requires an application to update an attacker-controlled existing archive; the affected worker then parses the same header indefinitely.

CVSS severity8.7
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Isaac Z. Schlueter tar before 7.5.18 allows remote attackers to hang workers via a crafted archive. The tar.replace scanner accepts a checksum-valid negative base-256 size and adds it to the 512-byte header step, leaving its position unchanged. Exploitation requires an application to update an attacker-controlled existing archive; the affected worker then parses the same header indefinitely.

The record

CVE
CVE-2026-59874
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
Isaac Z. Schlueter
Product
tar
Classifications
CWE-835, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 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=< 7.5.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Isaac Z. Schlueter · tarversion=< 7.5.18

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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 exploitPublished

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.004Application or System Exploitation

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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