boxscore/security
CVE · referencelatest edition

Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-9545HIGH
curl curl — exposing HTTP/3 early data
  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  H  N  N    7.5   .0027   19.1     —
AFFECTED
  Product  Versions  Fixed
  curl     8.20.0 –  —
TIMELINE
  May 26  Reserved by curl
  Jul 3   EXPLOIT PUBLISHED — CVE-2026-9545 (curl). Public exploit reference added.
  Jul 3   Published (CNA: curl)
CNA: curl · CVSS v3.1 · 3 references · NVD status: Analyzed

Description

In this scenario, libcurl first uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate. When libcurl returns to the hostname the second time with a cached SSL session (`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the `CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might send off the second request's bytes on that new connection *before* enforcing the certificate verification failure. Potentially leaking sensitive information.

Lifecycle

Complete event history — 3 events, chronological
DateEventDetail
May 26, 2026ReservedReserved by curl
July 3, 2026EXPLOIT PUBLISHEDEXPLOIT PUBLISHED — CVE-2026-9545 (curl). Public exploit reference added.
July 3, 2026PublishedPublished (CNA: curl)

Affected

Affected products and packages — 1 row
VendorProduct / PackageEcosystemVersion introducedFixed
curlcurl8.20.0

References (3)

Related

Authoritative record: CVE-2026-9545 at cve.org

Vendors: curl

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-9545 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.