CyberRota Analysis
AI-GeneratedThe vulnerability affects rustls-webpki versions up to 0.103.12 and 0.104.0-alpha prior to 0.104.0-alpha.7, specifically in the bit_string_flags() function, which can lead to a denial of service due to a panic caused by an improperly formatted Certificate Revocation List (CRL). Applications that enable CRL revocation checking and process CRL data from untrusted sources are at risk, making it critical for developers using these versions to upgrade to 0.103.13 or 0.104.0-alpha.7 to mitigate the issue. Organizations relying on rustls for secure communications should prioritize this update to prevent potential service disruptions.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
rustls-webpki through 0.103.12 (and 0.104.0-alpha releases before 0.104.0-alpha.7) contains a reachable panic in bit_string_flags() in src/der.rs. The input guard fails to reject a named-bit BIT STRING whose content is exactly [0x00] (zero padding bits and no data bytes), so raw_bits.len() - 1 underflows on the empty slice and the subsequent index operation panics (subtract-with-overflow in debug, index-out-of-bounds in release). The condition is reachable through the public API BorrowedCertRevocationList::from_der() when a CRL contains an issuingDistributionPoint extension with such an onlySomeReasons value. Exploitation requires an application that explicitly opts in to CRL revocation checking by passing RevocationOptions to verify_for_usage() and that parses CRL bytes obtained from a source the attacker can influence; the default rustls configuration, which does not use RevocationOptions, is unaffected. A crafted CRL causes a denial of service via the panic. Fixed in 0.103.13 and 0.104.0-alpha.7.