CVE-2021-29488Network attack vector

Arbitrary file creation via malicious PAR2 filenames

Published May 7, 2021 · Updated Aug 3, 2024

Path traversal in SABnzbd before 3.0.0 on Windows or before 3.2.1 elsewhere allows attackers to write files via malicious PAR2 names. The quick_check_set path joins an attacker-controlled PAR2 filename to the job download path, and filesystem.renamer() moves the file without verifying containment. Exploitation requires a crafted NZB to enter the queue and retrieve the attacker's PAR2 content; writes are limited to new files in locations accessible to the SABnzbd process.

CVSS severityUnavailable
Unscored
EPSS probability0.92%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Path traversal in SABnzbd before 3.0.0 on Windows or before 3.2.1 elsewhere allows attackers to write files via malicious PAR2 names. The quick_check_set path joins an attacker-controlled PAR2 filename to the job download path, and filesystem.renamer() moves the file without verifying containment. Exploitation requires a crafted NZB to enter the queue and retrieve the attacker's PAR2 content; writes are limited to new files in locations accessible to the SABnzbd process.

The record

CVE
CVE-2021-29488
Published
May 7, 2021
Updated
Aug 3, 2024
Vendor
SABnzbd
Product
SABnzbd
Classifications
T1105
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 3.0.0
  2. Affected versionversion=< 3.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SABnzbd · SABnzbdversion=< 3.0.0; version=< 3.2.1

Published CVSS scores

No CVSS assessment is available in this record.

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

T1105Ingress Tool Transfer

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo