DEBIAN-CVE-2026-55520
Protego is a pure-Python robots.txt parser with support for modern conventions. Prior to 0.6.2, protego._urlpattern._URLPattern._prepare_pattern_for_regex translates every asterisk in an Allow or Disallow directive into a lazy regular-expression wildcard, so a directive containing many asterisks creates exponential backtracking. After protego.Protego.parse processes a crafted robots.txt file, protego.Protego.can_fetch can spend an attacker-controlled period matching a near-miss URL and deny service to the crawler. The vulnerable path is src/protego/_urlpattern.py in the _URLPattern match logic. This issue is fixed in version 0.6.2.
DEBIAN-CVE-2026-55520
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-55520
python-protego
Source reference: /affected/0/package/name
- Affected versions
- 0.2.1+dfsg-1
Source reference:
/affected/0/versions0.3.0+dfsg-1Source reference:
/affected/0/versions0.3.1+dfsg-1Source reference:
/affected/0/versions0.4.0+dfsg-1Source reference:
/affected/0/versions0.5.0+dfsg-1Source reference:
/affected/0/versions0.6.0+dfsg-1Source reference:
/affected/0/versions0.6.2+dfsg-1Source reference:
/affected/0/versions0.7.0+dfsg-1Source reference:
/affected/0/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
python-protego
Source reference: /affected/1/package/name
- Affected versions
- 0.4.0+dfsg-1
Source reference:
/affected/1/versions0.5.0+dfsg-1Source reference:
/affected/1/versions0.6.0+dfsg-1Source reference:
/affected/1/versions0.6.2+dfsg-1Source reference:
/affected/1/versions0.7.0+dfsg-1Source reference:
/affected/1/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
python-protego
Source reference: /affected/2/package/name
- Affected versions
- 0.4.0+dfsg-1
Source reference:
/affected/2/versions0.5.0+dfsg-1Source reference:
/affected/2/versions0.6.0+dfsg-1Source reference:
/affected/2/versions - Fixed versions
- 0.6.2+dfsg-1
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "python-protego",
"purl": "pkg:deb/debian/python-protego?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"0.2.1+dfsg-1",
"0.3.0+dfsg-1",
"0.3.1+dfsg-1",
"0.4.0+dfsg-1",
"0.5.0+dfsg-1",
"0.6.0+dfsg-1",
"0.6.2+dfsg-1",
"0.7.0+dfsg-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-55520.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "python-protego",
"purl": "pkg:deb/debian/python-protego?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"0.4.0+dfsg-1",
"0.5.0+dfsg-1",
"0.6.0+dfsg-1",
"0.6.2+dfsg-1",
"0.7.0+dfsg-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-55520.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "0.6.2+dfsg-1"
}
]
}
],
"package": {
"name": "python-protego",
"purl": "pkg:deb/debian/python-protego?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"0.4.0+dfsg-1",
"0.5.0+dfsg-1",
"0.6.0+dfsg-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-55520.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #57941 · Revision 1
- Added to Heist Feed
- Publisher date