PYSEC-2026-1969
Vulnerability from pysec - Published: 2026-07-07 11:45 - Updated: 2026-07-07 17:25Summary
The torbot.modules.validators.validate_link function uses the python-validators URL validation regex. This particular regular expression has an exponential complexity which allows an attacker to cause an application crash using a well-crafted argument..
Details
https://github.com/DedSecInside/TorBot/blob/d2b89192379ad033ffc7044efff26e16ccc02d5a/torbot/modules/validators.py#L13
An attacker can use a well-crafted URL argument to exploit the vulnerability in the regular expression and cause a Denial of Service on the system.
PoC
I have uploaded a secret gist containing a PoC (https://gist.github.com/ikkebr/6041055314f1cfb8e65b2a1acbaae12c). By adding one special character at the end of the user argument of the URL, the regular expression will take exponentially longer to compute.
For a string of size 10k, the regex will take 0.01s without the well-crafted URL and 1.3s with the well-crafted URL exploit. For a string of size 50k, the regex will take 0.03s without the well-crafted URL and 35s with the well-crafted URL exploit. For a string of size 100k, the regex will take 0.05s without the well-crafted URL and over 200s with the well-crafted URL exploit.
The regular expression used in the validators library versions [0.20, 0.11] is vulnerable to this attack. Version 0.21 appears to be unaffected, but it no longer contains a single regular expression.
Impact
An attacker could exploit this vulnerability to cause a denial of service or increased resource usage.
| Name | purl | torbot | pkg:pypi/torbot |
|---|
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "torbot",
"purl": "pkg:pypi/torbot"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.0.0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.2",
"2.1.0",
"3.0.1",
"3.1.1",
"3.1.2"
]
}
],
"aliases": [
"CVE-2023-45813",
"GHSA-72qw-p7hh-m3ff"
],
"details": "### Summary\n_The torbot.modules.validators.validate_link function uses the python-validators URL validation regex. This particular regular expression has an exponential complexity which allows an attacker to cause an application crash using a well-crafted argument.._\n\n### Details\nhttps://github.com/DedSecInside/TorBot/blob/d2b89192379ad033ffc7044efff26e16ccc02d5a/torbot/modules/validators.py#L13\n\nAn attacker can use a well-crafted URL argument to exploit the vulnerability in the regular expression and cause a Denial of Service on the system.\n\n### PoC\nI have uploaded a secret gist containing a PoC (https://gist.github.com/ikkebr/6041055314f1cfb8e65b2a1acbaae12c). By adding one special character at the end of the user argument of the URL, the regular expression will take exponentially longer to compute.\n\nFor a string of size 10k, the regex will take 0.01s without the well-crafted URL and 1.3s with the well-crafted URL exploit.\nFor a string of size 50k, the regex will take 0.03s without the well-crafted URL and 35s with the well-crafted URL exploit.\nFor a string of size 100k, the regex will take 0.05s without the well-crafted URL and over 200s with the well-crafted URL exploit.\n\nThe regular expression used in the validators library versions [0.20, 0.11] is vulnerable to this attack. Version 0.21 appears to be unaffected, but it no longer contains a single regular expression.\n\n### Impact\nAn attacker could exploit this vulnerability to cause a denial of service or increased resource usage.\n",
"id": "PYSEC-2026-1969",
"modified": "2026-07-07T17:25:41.961260Z",
"published": "2026-07-07T11:45:25.857668Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/DedSecInside/TorBot/security/advisories/GHSA-72qw-p7hh-m3ff"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-45813"
},
{
"type": "WEB",
"url": "https://github.com/DedSecInside/TorBot/commit/ef6e06bc7785355b1701d5524eb4550441086ac4"
},
{
"type": "WEB",
"url": "https://gist.github.com/ikkebr/6041055314f1cfb8e65b2a1acbaae12c"
},
{
"type": "PACKAGE",
"url": "https://github.com/DedSecInside/TorBot"
},
{
"type": "WEB",
"url": "https://github.com/DedSecInside/TorBot/blob/d2b89192379ad033ffc7044efff26e16ccc02d5a/torbot/modules/validators.py#L13"
},
{
"type": "PACKAGE",
"url": "https://pypi.org/project/torbot"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-72qw-p7hh-m3ff"
}
],
"severity": [
{
"score": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "TorBot vulnerable to Inefficient Regular Expression Complexity in validate_link"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.