What’s Vulnerable › Vulnerabilities

CVE-2021-29922

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-08-07 · updated 2026-06-17

Description

library/std/src/net/parser.rs in Rust before 1.53.0 does not properly consider extraneous zero characters at the beginning of an IP address string, which (in some situations) allows attackers to bypass access control that is based on IP addresses, because of unexpected octal interpretation.

Affected products

• rust-lang rust: before 1.53.0 — fixed in 1.53.0

How to fix

Upgrade to a fixed version: rust-lang rust 1.53.0. Check the vendor advisory for mitigations.

References

• https://defcon.org/html/defcon-29/dc-29-speakers.html#kaoudis
• https://doc.rust-lang.org/beta/std/net/struct.Ipv4Addr.html
• https://github.com/rust-lang/rust/issues/83648
• https://github.com/rust-lang/rust/pull/83652
• https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-015.md
• https://security.gentoo.org/glsa/202210-09
• https://defcon.org/html/defcon-29/dc-29-speakers.html#kaoudis
• https://doc.rust-lang.org/beta/std/net/struct.Ipv4Addr.html
• https://github.com/rust-lang/rust/issues/83648
• https://github.com/rust-lang/rust/pull/83652
• https://github.com/sickcodes/security/blob/master/advisories/SICK-2021-015.md
• https://security.gentoo.org/glsa/202210-09

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