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CVE-2026-8927

Critical9.1

When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.

CVSS
9.1v3.1
EPSS (exploit probability)
0.5%42th pct
CISA KEV
Not listed

EPSS trendFIRST daily scores, last 90 days

FIRST EPSS held steady from 0.5% on 2026-09-18 to 0.5% on 2026-10-20, ranging 0.5%–0.5% across 31 daily scores.
2026-09-18 → 2026-10-20 · 31 days · 0.5%–0.5%
Daily values
FIRST EPSS daily scores for this CVE
Score dateEPSSPercentile
2026-10-200.5%41.7%
2026-10-190.5%41.6%
2026-10-180.5%41.5%
2026-10-160.5%41.5%
2026-10-150.5%41.5%
2026-10-140.5%41.4%
2026-10-130.5%41.2%
2026-10-120.5%41.1%
2026-10-110.5%41.1%
2026-10-100.5%41.0%
2026-10-090.5%41.0%
2026-10-080.5%40.9%
2026-10-070.5%40.9%
2026-10-060.5%40.8%
2026-10-050.5%40.7%
2026-10-040.5%40.7%
2026-10-030.5%40.7%
2026-10-020.5%40.7%
2026-10-010.5%40.6%
2026-09-300.5%40.6%
2026-09-290.5%40.5%
2026-09-270.5%40.4%
2026-09-260.5%40.4%
2026-09-250.5%40.3%
2026-09-240.5%40.2%
2026-09-230.5%41.9%
2026-09-220.5%41.9%
2026-09-210.5%41.7%
2026-09-200.5%41.9%
2026-09-190.5%41.9%
2026-09-180.5%41.9%

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

  • haxx curl

Coverage1 article

References

Facts sourced from NVD, FIRST EPSS, and CISA KEV. Last synced 2026-10-21 07:34 UTC.

  • CVSS & description: NVD 2.0, fetched 2026-10-21 06:34 UTC
  • EPSS: FIRST EPSS, fetched 2026-10-21 07:34 UTC; score date 2026-10-20
  • KEV: CISA KEV, fetched 2026-10-21 07:34 UTC