Service interruption via signed-byte URI encoding
Published Nov 3, 2023 · Updated Feb 25, 2026
Incorrect numeric conversion in Squid 5.0.3 through 6.3 allows remote attackers to interrupt proxy service via crafted FTP URLs. AnyP::Uri::Encode promotes signed URL bytes directly to unsigned integers during percent-encoding, so high-bit bytes expand beyond the intended two hexadecimal digits. The path runs during access-control checks before permission to use the proxy is established, and FTP URL handling cannot be disabled completely.
Summary
What happened
Incorrect numeric conversion in Squid 5.0.3 through 6.3 allows remote attackers to interrupt proxy service via crafted FTP URLs. AnyP::Uri::Encode promotes signed URL bytes directly to unsigned integers during percent-encoding, so high-bit bytes expand beyond the intended two hexadecimal digits. The path runs during access-control checks before permission to use the proxy is established, and FTP URL handling cannot be disabled completely.
The record
- CVE
- CVE-2023-46848
- Published
- Nov 3, 2023
- Updated
- Feb 25, 2026
- Vendor
- Red Hat
- Product
- Red Hat Enterprise Linux 9.0 Extended Update Support
- Classifications
- CWE-681, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 3, 2023CVE publishedPublication date reported by the CVE source.
- Feb 25, 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?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
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
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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