CVE catalog

CVE-2026-55520

python-protego: CVE-2026-55520

Severity: High · CVSS 7.1CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published: Jul 7, 2026, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 0.51% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	python-protego	sid	`0.7.0+dfsg-1`	fixed
Debian	python-protego	forky	`0.7.0+dfsg-1`	fixed
Debian	python-protego	trixie	`0.4.0+dfsg-1`	vulnerable
Debian	python-protego	bookworm	`0.2.1+dfsg-1`	vulnerable
Pip	Protego	Not reported	`0.6.2`	fixed
Opensuse	python-Protego	tumbleweed	`0.6.2-1.1`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	python-protego	source	sid	`0.6.2+dfsg-1`	not yet assigned	Not reported	Not reported
Debian	python-protego	source	forky	`0.6.2+dfsg-1`	not yet assigned	Not reported	Not reported
Debian	python-protego	source	trixie	`(unfixed)`	not yet assigned	Not reported	Not reported
Debian	python-protego	source	bookworm	`(unfixed)`	not yet assigned	Not reported	Not reported
Pip	Protego	pip	Not reported	`0.6.2`	Not reported	GHSA-WJMF-P669-5M5P	Not reported
Opensuse	python-Protego	rpm	tumbleweed	`0.6.2-1.1`	Not reported	OPENSUSE-SU-2026:11202-1	Not reported

Notes

[trixie] python-protego: Minor issue [bookworm] python-protego: Minor issue

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[python3-protego]Affected
Source package: [python-protego]
Details (2)
- 0.2.1+dfsg-1 · all · bookworm
  Affected
  dsa · python-protego · debian · bookworm; dsa · python-protego · debian · 12
- 0.2.1+dfsg-1 · all · bookworm
  Affected
  dsa · python-protego · debian · bookworm; dsa · python-protego · debian · 12

[Debian 13 (Trixie)]

[python3-protego]Affected
Source package: [python-protego]
Details (2)
- 0.4.0+dfsg-1 · all · trixie
  Affected
  dsa · python-protego · debian · 13
- 0.4.0+dfsg-1 · all · trixie
  Affected
  dsa · python-protego · debian · 13

[openSUSE Tumbleweed]

[python313-Protego]Unknown
Source package: [python-Protego]
Details (1)
- 0.6.2-1.2 · noarch · tumbleweed
  Unknown · Fixed: 0.6.2-1.1
  Version impact unknown
  dsa · python-Protego · opensuse · tumbleweed
[python314-Protego]Unknown
Source package: [python-Protego]
Details (1)
- 0.6.2-1.2 · noarch · tumbleweed
  Unknown · Fixed: 0.6.2-1.1
  Version impact unknown
  dsa · python-Protego · opensuse · tumbleweed

Observed: Oct 23, 2026, 9:44:31 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]