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Product · h2o

quicly

6 known vulnerabilities.

quicly at a glance

Last 12 months
5
Critical · all time
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New vulnerabilities per month · last 12 months
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All Critical High Medium Low Exploited only Public exploit

6 results · Feed

  • High 7.5
    CVE-2026-44436

    Quicly is vulnerable to connection state corruption

    Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server. Prior to commit 8b178e6, Quicly is vulnerable to a Denial of Service attack through connection state corruption. In QUIC Invariants, the maximum length of a …

    h2o quicly
  • High 7.5
    CVE-2026-44435

    Quicly: Remote Denial of Service via assertion failure when CRYPTO stream handshake data exceeds 32KB

    Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server. Prior to commit 937d0e9, an assertion failure is raised when the total number of valid handshake messages received over a CRYPTO stream of a single packet nu…

    h2o quicly
  • Medium 5.3
    CVE-2026-44434

    Quicly is vulnerable to stateless reset injection

    Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server. Prior to commit dccf5d4, Quicly was vulnerable to stateless reset injection through lack of packet entry validation. The QUIC protocol is designed to withsta…

    h2o quicly
  • Medium 5.3
    CVE-2026-44433

    Quicly is vulnerable to memory exhaustion

    Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server. Prior to commit 8b178e6, an adversarial peer could send a STREAM frame carrying just one byte at the largest offset being permitted to obtain additional flow…

    h2o quicly
  • High 7.5
    CVE-2025-61684

    Quicly has assertion failures

    Quicly, an IETF QUIC protocol implementation, is susceptible to a denial-of-service attack prior to commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using Quicly. Co…

    h2o quicly
  • High 7.5
    CVE-2024-45396

    Quicly assertion failures

    Quicly is an IETF QUIC protocol implementation. Quicly up to commtit d720707 is susceptible to a denial-of-service attack. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using quicly. The vulnerability is address…

    h2o quicly