Tor before 0.2.4.26 and 0.2.5.x before 0.2.5.11 does not properly handle pending-connection resolve states during periods of high DNS load, which allows remote attackers to cause a denial of service (assertion failure and daemon exit) via crafted packets
Published Jan 24, 2020
7.5
HIGHCVSS 3.1
EPSS 2.19%
Description
Tor before 0.2.4.26 and 0.2.5.x before 0.2.5.11 does not properly handle pending-connection resolve states during periods of high DNS load, which allows remote attackers to cause a denial of service (assertion failure and daemon exit) via crafted packets.
Affected products
-
- Version 0.2.5.x before 0.2.5.11StatusaffectedConstraints-
- Version before 0.2.4.26StatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| The Tor Project | Tor | n/a |
|
- < 0.2.4.26
- ≥ 0.2.5.1 · < 0.2.5.11
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
No CVSS v3.0 score for this CVE.
AV:N/AC:L/Au:N/C:N/I:N/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (12 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 2.19% (0.02185) | 81.73th | v5 (v2026.06.15) |
| Jun 15, 2026 | 2.19% (0.02185) | 79.97th | v5 (v2026.06.15) |
| Mar 30, 2025 | 0.65% (0.00648) | 68.38th | v4 (v2025.03.14) |
| Mar 29, 2025 | 1.77% (0.01766) | 71.34th | v4 (v2025.03.14) |
| Mar 17, 2025 | 0.65% (0.00648) | 69.05th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.20% (0.00202) | 59.11th | v3 (v2023.03.01) |
| Jun 12, 2024 | 0.20% (0.00202) | 58.32th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.20% (0.00202) | 56.32th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.05% (0.01055) | 52.13th | v2 (v2022.01.01) |
| Sep 17, 2022 | 1.05% (0.01055) | 50.47th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.05% (0.01055) | 48.43th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.05% (0.01055) | 27.52th | v2 (v2022.01.01) |
References (2)
- https://lists.torproject.org/pipermail/tor-talk/2015-March/037281.html x_refsource_MISCMailing ListVendor Advisory
- https://trac.torproject.org/projects/tor/ticket/14129 x_refsource_MISCPatchVendor Advisory
| Link | Providers | Tags |
|---|---|---|
| https://lists.torproject.org/pipermail/tor-talk/2015-March/037281.html | x_refsource_MISCMailing ListVendor Advisory | |
| https://trac.torproject.org/projects/tor/ticket/14129 | x_refsource_MISCPatchVendor Advisory |
Change history (0)
No recorded changes yet.