CVE-2026-55520

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Source
https://cve.org/CVERecord?id=CVE-2026-55520
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55520.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-55520
Aliases
Downstream
Related
Published
2026-08-28T18:42:38Z
Modified
2026-10-28T02:30:28Z
Severity
  • 7.1 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CVSS Calculator
Summary
Protego: Exponential backtracking ReDoS in robots.txt URL wildcard matching
Details

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.

Database specific 
{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-1333",
        "CWE-400"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55520.json"
}
References

Affected packages

Git / github.com/scrapy/protego

Affected ranges

Type
GIT
Repo
https://github.com/scrapy/protego
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
efe5039d39ee51f117acd0b01ffd8109ae265c22
Fixed
785940181659bf440ba82f1da148fade5087e858
Database specific
Show details 
{
    "extracted_events":  [
        {
            "range":  [
                {
                    "introduced":  "0"
                },
                {
                    "fixed":  "0.6.2"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StringRangeExpression"
        },
        {
            "range":  [
                {
                    "fixed":  "785940181659bf440ba82f1da148fade5087e858"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "original_tag":  "0.6.2",
            "range":  [
                {
                    "fixed":  "efe5039d39ee51f117acd0b01ffd8109ae265c22"
                }
            ],
            "source":  "REFERENCES_TAG"
        }
    ]
}

Affected versions

0.*
0.1.10
0.1.11
0.1.12
0.1.13
0.1.14
0.1.15
0.1.16
0.1.3
0.1.4
0.1.5
0.1.6
0.1.7
0.1.8
0.1.9
0.2.0
0.2.1
0.3.0
0.3.1
0.4.0
0.5.0
0.6.0
0.6.1
v0.*
v0.1
v0.1.1
v0.1.2

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55520.json"