Vulnerability in Curl
CVE-2026-8458
libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use different "services". libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different services.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.004 (29.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 29.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.004 · change: -0.002
Affected products
Weakness classification (CWE)
References
- 2499f714-1537-4658-8207-48ae4bb9eae9 (Vendor Advisory)
- 2499f714-1537-4658-8207-48ae4bb9eae9 (Patch, Vendor Advisory)
- 2499f714-1537-4658-8207-48ae4bb9eae9 (Exploit, Third Party Advisory, Issue Tracking)
Frequently asked questions
- What is CVE-2026-8458?
- CVE-2026-8458 is a medium-severity vulnerability in Curl, classified under CWE-488. CVSS score: 6.5/10. Published 2026-07-03.
- How severe is CVE-2026-8458?
- Medium severity. CVSS v3 base score is 6.5 out of 10.