CVE-2015-2928Network attack vector

Remote daemon halt via reachable assertion

Published Jan 24, 2020 · Updated Aug 6, 2024

Denial of service in Tor hidden-service servers allows remote attackers to halt affected daemons by sending a malicious client request. The Tor Project has not disclosed the specific hidden-service code path or client input that reaches the fatal assertion. Exposure requires hidden-service server operation and affects Tor before 0.2.4.27, 0.2.5.x before 0.2.5.12, and 0.2.6.x before 0.2.6.7; no code execution or anonymity loss is reported.

CVSS severity7.5
High
EPSS probability1.38%
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 Tor hidden-service servers allows remote attackers to halt affected daemons by sending a malicious client request. The Tor Project has not disclosed the specific hidden-service code path or client input that reaches the fatal assertion. Exposure requires hidden-service server operation and affects Tor before 0.2.4.27, 0.2.5.x before 0.2.5.12, and 0.2.6.x before 0.2.6.7; no code execution or anonymity loss is reported.

The record

CVE
CVE-2015-2928
Published
Jan 24, 2020
Updated
Aug 6, 2024
Vendor
The Tor Project
Product
Tor
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 24, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 6, 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?

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

  1. Affected versionversion=0.2.5.x before 0.2.5.12
  2. Affected versionversion=0.2.6.x before 0.2.6.7
  3. Affected versionversion=before 0.2.4.27

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Tor Project · Torversion=0.2.5.x before 0.2.5.12; version=0.2.6.x before 0.2.6.7; version=before 0.2.4.27

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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.

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

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

T1499.004Application or System Exploitation

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

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Your stack

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