Tor up to 0.4.9.7 off-by-one

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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3.7$5k-$25k0.00

Summaryinfo

A vulnerability was found in Tor up to 0.4.9.7. It has been declared as problematic. The impacted element is an unknown function. Such manipulation leads to off-by-one. This vulnerability is listed as CVE-2026-44603. The attack may be performed from remote. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Tor up to 0.4.9.7. It has been rated as problematic. Affected by this issue is some unknown processing. The manipulation with an unknown input leads to a off-by-one vulnerability. Using CWE to declare the problem leads to CWE-193. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value. Impacted is availability. CVE summarizes:

Tor before 0.4.9.7 has an out-of-bounds read by one byte via a malformed BEGIN cell, aka TROVE-2026-007.

The advisory is shared for download at forum.torproject.org. This vulnerability is handled as CVE-2026-44603 since 05/07/2026. The exploitation is known to be difficult. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 05/13/2026).

The vulnerability scanner Nessus provides a plugin with the ID 313064 (Linux Distros Unpatched Vulnerability : CVE-2026-44603), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 0.4.9.7 eliminates this vulnerability. Applying the patch 1703df3d439c83c2184e259fad1cfa19240f9c89 is able to eliminate this problem. The bugfix is ready for download at gitlab.torproject.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (313064), EUVD (EUVD-2026-28306) and CERT Bund (WID-SEC-2026-1398). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Debian Linux
  • SUSE openSUSE
  • Open Source Tor

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.7

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 3.7
CNA Vector (MITRE): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Off-by-one
CWE: CWE-193 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 313064
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-44603

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Tor 0.4.9.7
Patch: 1703df3d439c83c2184e259fad1cfa19240f9c89

Timelineinfo

05/07/2026 Advisory disclosed
05/07/2026 +0 days CVE reserved
05/07/2026 +0 days VulDB entry created
05/13/2026 +6 days VulDB entry last update

Sourcesinfo

Advisory: forum.torproject.org
Status: Confirmed

CVE: CVE-2026-44603 (🔒)
GCVE (CVE): GCVE-0-2026-44603
GCVE (VulDB): GCVE-100-361808
EUVD: 🔒
CERT Bund: WID-SEC-2026-1398 - Tor: Mehrere Schwachstellen

Entryinfo

Created: 05/07/2026 07:45
Updated: 05/13/2026 15:31
Changes: 05/07/2026 07:45 (64), 05/07/2026 10:23 (1), 05/08/2026 05:23 (2), 05/13/2026 15:31 (7)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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