SSRF protection bypass via IPv6 validation gaps
Published Sep 15, 2026 · Updated Sep 15, 2026
SSRF in Doyensec safeurl 0.1.0 and later allows attackers to reach blocked internal destinations via attacker-controlled URLs. The address-matching path checks only IPv4 results against reserved ranges and the blocklist, treating IPv6 and hosts without IPv4 results as unmatched and therefore allowed. The bypass applies to blocklist-based deployments when an attacker controls a validated URL; allowlist-based deployments reject unmatched addresses and are unaffected.
Summary
What happened
SSRF in Doyensec safeurl 0.1.0 and later allows attackers to reach blocked internal destinations via attacker-controlled URLs. The address-matching path checks only IPv4 results against reserved ranges and the blocklist, treating IPv6 and hosts without IPv4 results as unmatched and therefore allowed. The bypass applies to blocklist-based deployments when an attacker controls a validated URL; allowlist-based deployments reject unmatched addresses and are unaffected.
The record
- CVE
- CVE-2026-77866
- Published
- Sep 15, 2026
- Updated
- Sep 15, 2026
- Vendor
- Doyensec
- Product
- safeurl
- Classifications
- Unavailable
- Attack vector
- network
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 15, 2026CVE publishedPublication date reported by the CVE source.
- Sep 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0.1.0 <*
- Affected versionversion=feabbd0a13f83028ab24b71710526e9da9841f70 <*
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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