CVE-2015-2929Network attack vector

Client crash via malformed hidden-service descriptor parsing

Published Jan 24, 2020 · Updated Aug 6, 2024

Denial of service in 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 allows remote servers to crash clients. The hidden-service descriptor parser processes a malformed server-supplied descriptor until an invariant check triggers an assertion instead of rejecting the input. Any server selected to supply a descriptor can therefore exit the client process and interrupt Tor connections, without reported confidentiality or integrity impact.

CVSS severity7.5
High
EPSS probability1.16%
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 before 0.2.4.27, 0.2.5.x before 0.2.5.12, and 0.2.6.x before 0.2.6.7 allows remote servers to crash clients. The hidden-service descriptor parser processes a malformed server-supplied descriptor until an invariant check triggers an assertion instead of rejecting the input. Any server selected to supply a descriptor can therefore exit the client process and interrupt Tor connections, without reported confidentiality or integrity impact.

The record

CVE
CVE-2015-2929
Published
Jan 24, 2020
Updated
Aug 6, 2024
Vendor
The Tor Project
Product
Tor
Classifications
T1499
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
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

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

T1499Endpoint Denial of Service

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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