CVE-2026-93599

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.

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Produits concernés

• rustls webpki

Scores CVSS

Faiblesses (CWE)

• CWE-191

Références

• https://github.com/rustls/webpki/security/advisories/GHSA-82j2-j2ch-gfr8
• https://www.vulncheck.com/advisories/rustls-webpki-before-0.103.13-panic-via-empty-bit-string
• https://github.com/rustls/webpki/security/advisories/GHSA-82j2-j2ch-gfr8

Ailleurs

• NVD
• CVE.org
• CIRCL Vulnerability-Lookup
• CERT-FR
• GitHub Advisories